diff --git a/docs/repo-specific-configuration.md b/docs/repo-specific-configuration.md
index 4463afc6d2..8601388eef 100644
--- a/docs/repo-specific-configuration.md
+++ b/docs/repo-specific-configuration.md
@@ -201,6 +201,10 @@ reviewers = [ "username1", "username2" ]
 # If true, Scala Steward will sign off all commits (e.g. `git --signoff`).
 # Default: false
 signoffCommits = true
+
+# Repos whose last commit is older than this threshold are considered
+# inactive and are ignored.
+inactivityThreshold = "90 days"
 ```
 
 The version information given in the patterns above can be in two formats:
diff --git a/modules/core/src/main/resources/default.scala-steward.conf b/modules/core/src/main/resources/default.scala-steward.conf
index af88ea9700..2802f925cb 100644
--- a/modules/core/src/main/resources/default.scala-steward.conf
+++ b/modules/core/src/main/resources/default.scala-steward.conf
@@ -4,6 +4,11 @@
 //   Changes to this file are therefore immediately visible to all
 //   Scala Steward instances.
 
+// Repos whose last commit is older than this threshold are considered
+// inactive and are ignored. This setting can be overridden with a greater
+// value in your own repo config file.
+inactivityThreshold = "270 days"
+
 postUpdateHooks = [
   {
     groupId = "com.github.liancheng",
diff --git a/modules/core/src/main/scala/org/scalasteward/core/git/FileGitAlg.scala b/modules/core/src/main/scala/org/scalasteward/core/git/FileGitAlg.scala
index 8552d2391f..6e6dd65836 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/git/FileGitAlg.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/git/FileGitAlg.scala
@@ -25,7 +25,7 @@ import org.scalasteward.core.forge.ForgeType.*
 import org.scalasteward.core.git.FileGitAlg.{dotdot, gitCmd}
 import org.scalasteward.core.io.process.{ProcessFailedException, SlurpOptions}
 import org.scalasteward.core.io.{FileAlg, ProcessAlg, WorkspaceAlg}
-import org.scalasteward.core.util.Nel
+import org.scalasteward.core.util.{Nel, Timestamp}
 
 final class FileGitAlg[F[_]](config: Config)(implicit
     fileAlg: FileAlg[F],
@@ -102,6 +102,11 @@ final class FileGitAlg[F[_]](config: Config)(implicit
       .handleError(_ => List.empty[String])
       .map(_.filter(_.nonEmpty))
 
+  override def getCommitDate(repo: File, sha1: Sha1): F[Timestamp] =
+    git("show", "--no-patch", "--format=%ct", sha1.value.value)(repo)
+      .flatMap(out => F.catchNonFatal(out.mkString.trim.toLong))
+      .map(Timestamp.fromEpochSecond)
+
   override def hasConflicts(repo: File, branch: Branch, base: Branch): F[Boolean] = {
     val tryMerge = git_("merge", "--no-commit", "--no-ff", branch.name)(repo)
     val abortMerge = git_("merge", "--abort")(repo).attempt.void
diff --git a/modules/core/src/main/scala/org/scalasteward/core/git/GenGitAlg.scala b/modules/core/src/main/scala/org/scalasteward/core/git/GenGitAlg.scala
index c4240622fb..f89130c0d5 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/git/GenGitAlg.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/git/GenGitAlg.scala
@@ -22,6 +22,7 @@ import cats.{FlatMap, Monad}
 import org.http4s.Uri
 import org.scalasteward.core.application.Config
 import org.scalasteward.core.io.{FileAlg, ProcessAlg, WorkspaceAlg}
+import org.scalasteward.core.util.Timestamp
 
 trait GenGitAlg[F[_], Repo] {
   def add(repo: Repo, file: String): F[Unit]
@@ -57,6 +58,8 @@ trait GenGitAlg[F[_], Repo] {
 
   def findFilesContaining(repo: Repo, string: String): F[List[String]]
 
+  def getCommitDate(repo: Repo, sha1: Sha1): F[Timestamp]
+
   /** Returns `true` if merging `branch` into `base` results in merge conflicts. */
   def hasConflicts(repo: Repo, branch: Branch, base: Branch): F[Boolean]
 
@@ -144,6 +147,9 @@ trait GenGitAlg[F[_], Repo] {
       override def findFilesContaining(repo: A, string: String): F[List[String]] =
         f(repo).flatMap(self.findFilesContaining(_, string))
 
+      override def getCommitDate(repo: A, sha1: Sha1): F[Timestamp] =
+        f(repo).flatMap(self.getCommitDate(_, sha1))
+
       override def hasConflicts(repo: A, branch: Branch, base: Branch): F[Boolean] =
         f(repo).flatMap(self.hasConflicts(_, branch, base))
 
diff --git a/modules/core/src/main/scala/org/scalasteward/core/repocache/RepoCache.scala b/modules/core/src/main/scala/org/scalasteward/core/repocache/RepoCache.scala
index e1d098db43..c62d8e79e2 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/repocache/RepoCache.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/repocache/RepoCache.scala
@@ -22,9 +22,11 @@ import io.circe.generic.semiauto.*
 import org.scalasteward.core.data.{ArtifactId, DependencyInfo, GroupId, Scope}
 import org.scalasteward.core.git.Sha1
 import org.scalasteward.core.repoconfig.RepoConfig
+import org.scalasteward.core.util.Timestamp
 
 final case class RepoCache(
     sha1: Sha1,
+    commitDate: Timestamp,
     dependencyInfos: List[Scope[List[DependencyInfo]]],
     maybeRepoConfig: Option[RepoConfig],
     maybeRepoConfigParsingError: Option[String]
diff --git a/modules/core/src/main/scala/org/scalasteward/core/repocache/RepoCacheAlg.scala b/modules/core/src/main/scala/org/scalasteward/core/repocache/RepoCacheAlg.scala
index cf760bce6b..abfdbaa695 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/repocache/RepoCacheAlg.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/repocache/RepoCacheAlg.scala
@@ -24,11 +24,17 @@ import org.scalasteward.core.data.{Dependency, DependencyInfo, Repo, RepoData}
 import org.scalasteward.core.forge.data.RepoOut
 import org.scalasteward.core.forge.{ForgeApiAlg, ForgeRepoAlg}
 import org.scalasteward.core.git.GitAlg
+import org.scalasteward.core.repocache.RepoCacheAlg.RepositoryInactive
 import org.scalasteward.core.repoconfig.RepoConfigAlg
+import org.scalasteward.core.util.DateTimeAlg
+import org.scalasteward.core.util.dateTime.showDuration
 import org.typelevel.log4cats.Logger
+import scala.concurrent.duration.FiniteDuration
+import scala.util.control.NoStackTrace
 
 final class RepoCacheAlg[F[_]](config: Config)(implicit
     buildToolDispatcher: BuildToolDispatcher[F],
+    dateTimeAlg: DateTimeAlg[F],
     forgeApiAlg: ForgeApiAlg[F],
     forgeRepoAlg: ForgeRepoAlg[F],
     gitAlg: GitAlg[F],
@@ -50,6 +56,7 @@ final class RepoCacheAlg[F[_]](config: Config)(implicit
       data <- maybeCache
         .filter(_.sha1 === latestSha1)
         .fold(cloneAndRefreshCache(repo, repoOut))(supplementCache(repo, _).pure[F])
+      _ <- throwIfInactive(data)
     } yield (data, repoOut)
 
   private def supplementCache(repo: Repo, cache: RepoCache): RepoData =
@@ -68,7 +75,8 @@ final class RepoCacheAlg[F[_]](config: Config)(implicit
   private def computeCache(repo: Repo): F[RepoData] =
     for {
       branch <- gitAlg.currentBranch(repo)
-      latestSha1 <- gitAlg.latestSha1(repo, branch)
+      sha1 <- gitAlg.latestSha1(repo, branch)
+      commitDate <- gitAlg.getCommitDate(repo, sha1)
       configParsingResult <- repoConfigAlg.readRepoConfig(repo)
       maybeConfig = configParsingResult.maybeRepoConfig
       maybeConfigParsingError = configParsingResult.maybeParsingError.map(_.getMessage)
@@ -77,9 +85,30 @@ final class RepoCacheAlg[F[_]](config: Config)(implicit
       dependencyInfos <-
         dependencies.traverse(_.traverse(_.traverse(gatherDependencyInfo(repo, _))))
       _ <- gitAlg.discardChanges(repo)
-      cache = RepoCache(latestSha1, dependencyInfos, maybeConfig, maybeConfigParsingError)
+      cache = RepoCache(sha1, commitDate, dependencyInfos, maybeConfig, maybeConfigParsingError)
     } yield RepoData(repo, cache, config)
 
   private def gatherDependencyInfo(repo: Repo, dependency: Dependency): F[DependencyInfo] =
     gitAlg.findFilesContaining(repo, dependency.version.value).map(DependencyInfo(dependency, _))
+
+  private[repocache] def throwIfInactive(data: RepoData): F[Unit] =
+    data.config.inactivityThreshold.traverse_ { threshold =>
+      dateTimeAlg.currentTimestamp.flatMap { now =>
+        val inactiveSince = data.cache.commitDate.until(now)
+        val isInactive = inactiveSince > threshold
+        F.raiseWhen(isInactive)(RepositoryInactive(data.repo, inactiveSince, threshold))
+      }
+    }
+}
+
+object RepoCacheAlg {
+  final case class RepositoryInactive(
+      repo: Repo,
+      inactiveSince: FiniteDuration,
+      threshold: FiniteDuration
+  ) extends RuntimeException
+      with NoStackTrace {
+    override val getMessage: String =
+      s"${repo.show}, inactiveSince = ${showDuration(inactiveSince)}, threshold = ${showDuration(threshold)}"
+  }
 }
diff --git a/modules/core/src/main/scala/org/scalasteward/core/repoconfig/RepoConfig.scala b/modules/core/src/main/scala/org/scalasteward/core/repoconfig/RepoConfig.scala
index 708d87aa51..52298d29c2 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/repoconfig/RepoConfig.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/repoconfig/RepoConfig.scala
@@ -25,6 +25,9 @@ import org.scalasteward.core.buildtool.BuildRoot
 import org.scalasteward.core.data.Repo
 import org.scalasteward.core.edit.hooks.PostUpdateHook
 import org.scalasteward.core.repoconfig.RepoConfig.defaultBuildRoots
+import org.scalasteward.core.util.dateTime.*
+import org.scalasteward.core.util.{combineOptions, intellijThisImportIsUsed}
+import scala.concurrent.duration.FiniteDuration
 
 final case class RepoConfig(
     private val commits: Option[CommitsConfig] = None,
@@ -37,7 +40,8 @@ final case class RepoConfig(
     private val assignees: Option[List[String]] = None,
     private val reviewers: Option[List[String]] = None,
     private val dependencyOverrides: Option[List[GroupRepoConfig]] = None,
-    signoffCommits: Option[Boolean] = None
+    signoffCommits: Option[Boolean] = None,
+    inactivityThreshold: Option[FiniteDuration] = None
 ) {
   def commitsOrDefault: CommitsConfig =
     commits.getOrElse(CommitsConfig())
@@ -107,8 +111,12 @@ object RepoConfig {
               assignees = x.assignees |+| y.assignees,
               reviewers = x.reviewers |+| y.reviewers,
               dependencyOverrides = x.dependencyOverrides |+| y.dependencyOverrides,
-              signoffCommits = x.signoffCommits.orElse(y.signoffCommits)
+              signoffCommits = x.signoffCommits.orElse(y.signoffCommits),
+              inactivityThreshold =
+                combineOptions(x.inactivityThreshold, y.inactivityThreshold)(_ max _)
             )
         }
     )
+
+  intellijThisImportIsUsed(finiteDurationEncoder)
 }
diff --git a/modules/core/src/main/scala/org/scalasteward/core/util/Timestamp.scala b/modules/core/src/main/scala/org/scalasteward/core/util/Timestamp.scala
index 6e3513c53b..44aac04554 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/util/Timestamp.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/util/Timestamp.scala
@@ -34,6 +34,9 @@ final case class Timestamp(millis: Long) {
 }
 
 object Timestamp {
+  def fromEpochSecond(seconds: Long): Timestamp =
+    Timestamp(seconds * 1000L)
+
   def fromLocalDateTime(ldt: LocalDateTime): Timestamp =
     Timestamp(ldt.toInstant(ZoneOffset.UTC).toEpochMilli)
 
diff --git a/modules/core/src/main/scala/org/scalasteward/core/util/dateTime.scala b/modules/core/src/main/scala/org/scalasteward/core/util/dateTime.scala
index 88948db260..7624ef6aa4 100644
--- a/modules/core/src/main/scala/org/scalasteward/core/util/dateTime.scala
+++ b/modules/core/src/main/scala/org/scalasteward/core/util/dateTime.scala
@@ -17,6 +17,7 @@
 package org.scalasteward.core.util
 
 import cats.syntax.all.*
+import io.circe.{Decoder, Encoder}
 import java.util.concurrent.TimeUnit
 import scala.annotation.tailrec
 import scala.concurrent.duration.*
@@ -31,6 +32,12 @@ object dateTime {
   def renderFiniteDuration(fd: FiniteDuration): String =
     fd.toString.filterNot(_.isSpaceChar)
 
+  implicit val finiteDurationDecoder: Decoder[FiniteDuration] =
+    Decoder[String].emap(parseFiniteDuration(_).leftMap(_.getMessage))
+
+  implicit val finiteDurationEncoder: Encoder[FiniteDuration] =
+    Encoder[String].contramap(_.toString)
+
   def showDuration(d: FiniteDuration): String = {
     def symbol(unit: TimeUnit): String =
       unit match {
diff --git a/modules/core/src/test/scala/org/scalasteward/core/TestInstances.scala b/modules/core/src/test/scala/org/scalasteward/core/TestInstances.scala
index 0e98d94511..a2fa638f99 100644
--- a/modules/core/src/test/scala/org/scalasteward/core/TestInstances.scala
+++ b/modules/core/src/test/scala/org/scalasteward/core/TestInstances.scala
@@ -10,6 +10,7 @@ import org.scalasteward.core.git.Sha1
 import org.scalasteward.core.repocache.RepoCache
 import org.scalasteward.core.repoconfig.*
 import org.scalasteward.core.repoconfig.PullRequestFrequency.{Asap, Timespan}
+import org.scalasteward.core.util.{DateTimeAlg, Timestamp}
 import org.typelevel.log4cats.Logger
 import org.typelevel.log4cats.slf4j.Slf4jLogger
 import scala.concurrent.duration.FiniteDuration
@@ -19,11 +20,14 @@ object TestInstances {
     Sha1.unsafeFrom("da39a3ee5e6b4b0d3255bfef95601890afd80709")
 
   val dummyRepoCache: RepoCache =
-    RepoCache(dummySha1, List.empty, Option.empty, Option.empty)
+    RepoCache(dummySha1, Timestamp(0L), List.empty, Option.empty, Option.empty)
 
   val dummyRepoCacheWithParsingError: RepoCache =
     dummyRepoCache.copy(maybeRepoConfigParsingError = Some("Failed to parse .scala-steward.conf"))
 
+  val ioDateTimeAlg: DateTimeAlg[IO] =
+    DateTimeAlg.create[IO]
+
   implicit val ioLogger: Logger[IO] =
     Slf4jLogger.getLogger[IO]
 
diff --git a/modules/core/src/test/scala/org/scalasteward/core/git/FileGitAlgTest.scala b/modules/core/src/test/scala/org/scalasteward/core/git/FileGitAlgTest.scala
index 1105727787..45cfb40929 100644
--- a/modules/core/src/test/scala/org/scalasteward/core/git/FileGitAlgTest.scala
+++ b/modules/core/src/test/scala/org/scalasteward/core/git/FileGitAlgTest.scala
@@ -5,7 +5,7 @@ import cats.Monad
 import cats.effect.IO
 import cats.syntax.all.*
 import munit.CatsEffectSuite
-import org.scalasteward.core.TestInstances.ioLogger
+import org.scalasteward.core.TestInstances.{ioDateTimeAlg, ioLogger}
 import org.scalasteward.core.git.FileGitAlgTest.{
   conflictsNo,
   conflictsYes,
@@ -18,6 +18,7 @@ import org.scalasteward.core.io.ProcessAlgTest.ioProcessAlg
 import org.scalasteward.core.io.{FileAlg, ProcessAlg, WorkspaceAlg}
 import org.scalasteward.core.mock.MockConfig.{config, mockRoot}
 import org.scalasteward.core.util.Nel
+import scala.concurrent.duration.DurationInt
 
 class FileGitAlgTest extends CatsEffectSuite {
   private val rootDir = mockRoot / "git-tests"
@@ -158,6 +159,19 @@ class FileGitAlgTest extends CatsEffectSuite {
     } yield ()
   }
 
+  test("getCommitDate") {
+    val repo = rootDir / "getCommitDate"
+    for {
+      _ <- ioAuxGitAlg.createRepo(repo)
+      sha1 <- ioGitAlg.latestSha1(repo, master)
+      commitDate <- ioGitAlg.getCommitDate(repo, sha1)
+      now <- ioDateTimeAlg.currentTimestamp
+      diff = commitDate.until(now)
+      maxDrift = 2.hours
+      _ = assert(diff > -maxDrift && diff < maxDrift, clue((commitDate, now)))
+    } yield ()
+  }
+
   test("hasConflicts") {
     val repo = rootDir / "hasConflicts"
     for {
diff --git a/modules/core/src/test/scala/org/scalasteward/core/io/processTest.scala b/modules/core/src/test/scala/org/scalasteward/core/io/processTest.scala
index ef9d8b008c..34f09420bc 100644
--- a/modules/core/src/test/scala/org/scalasteward/core/io/processTest.scala
+++ b/modules/core/src/test/scala/org/scalasteward/core/io/processTest.scala
@@ -3,8 +3,9 @@ package org.scalasteward.core.io
 import cats.effect.IO
 import cats.effect.unsafe.implicits.global
 import munit.FunSuite
+import org.scalasteward.core.TestInstances.ioDateTimeAlg
 import org.scalasteward.core.io.process.*
-import org.scalasteward.core.util.{DateTimeAlg, Nel}
+import org.scalasteward.core.util.Nel
 import scala.concurrent.duration.*
 
 class processTest extends FunSuite {
@@ -66,7 +67,7 @@ class processTest extends FunSuite {
     val timeout = 500.milliseconds
     val sleep = timeout * 2
     val p = slurp2(Nel.of("sleep", sleep.toSeconds.toInt.toString), timeout).attempt
-    val (Left(t), fd) = DateTimeAlg.create[IO].timed(p).unsafeRunSync(): @unchecked
+    val (Left(t), fd) = ioDateTimeAlg.timed(p).unsafeRunSync(): @unchecked
 
     assert(clue(t).isInstanceOf[ProcessTimedOutException])
     assert(clue(fd) > timeout)
diff --git a/modules/core/src/test/scala/org/scalasteward/core/repocache/RepoCacheAlgTest.scala b/modules/core/src/test/scala/org/scalasteward/core/repocache/RepoCacheAlgTest.scala
index 26f79bbcfd..a71eaf47d1 100644
--- a/modules/core/src/test/scala/org/scalasteward/core/repocache/RepoCacheAlgTest.scala
+++ b/modules/core/src/test/scala/org/scalasteward/core/repocache/RepoCacheAlgTest.scala
@@ -1,7 +1,8 @@
 package org.scalasteward.core.repocache
 
-import cats.implicits.toSemigroupKOps
+import cats.syntax.all.*
 import io.circe.syntax.*
+import java.time.LocalDateTime
 import munit.CatsEffectSuite
 import org.http4s.HttpApp
 import org.http4s.circe.*
@@ -14,7 +15,10 @@ import org.scalasteward.core.forge.github.Repository
 import org.scalasteward.core.git.Branch
 import org.scalasteward.core.mock.MockContext.context.{repoCacheAlg, repoConfigAlg, workspaceAlg}
 import org.scalasteward.core.mock.{GitHubAuth, MockEff, MockEffOps, MockState}
-import org.scalasteward.core.util.intellijThisImportIsUsed
+import org.scalasteward.core.repocache.RepoCacheAlg.RepositoryInactive
+import org.scalasteward.core.repoconfig.RepoConfig
+import org.scalasteward.core.util.{intellijThisImportIsUsed, Timestamp}
+import scala.concurrent.duration.*
 
 class RepoCacheAlgTest extends CatsEffectSuite with Http4sDsl[MockEff] {
   intellijThisImportIsUsed(encodeUri)
@@ -36,7 +40,8 @@ class RepoCacheAlgTest extends CatsEffectSuite with Http4sDsl[MockEff] {
       uri"https://github.com/scala-steward/cats-effect.git",
       Branch("main")
     )
-    val repoCache = RepoCache(dummySha1, Nil, None, None)
+    val now = Timestamp.fromLocalDateTime(LocalDateTime.now())
+    val repoCache = RepoCache(dummySha1, now, Nil, None, None)
     val workspace = workspaceAlg.rootDir.unsafeRunSync()
     val httpApp = HttpApp[MockEff] {
       case POST -> Root / "repos" / "typelevel" / "cats-effect" / "forks" =>
@@ -55,4 +60,36 @@ class RepoCacheAlgTest extends CatsEffectSuite with Http4sDsl[MockEff] {
     val expected = (RepoData(repo, repoCache, repoConfigAlg.mergeWithGlobal(None)), repoOut)
     assertIO(obtained, expected)
   }
+
+  test("throwIfInactive: no threshold") {
+    val repo = Repo("repo-cache-alg", "test-1")
+    val cache = RepoCache(dummySha1, Timestamp(0L), Nil, None, None)
+    val config = RepoConfig.empty
+    val data = RepoData(repo, cache, config)
+    val obtained = repoCacheAlg.throwIfInactive(data).runA(MockState.empty).attempt
+    assertIO(obtained, Right(()))
+  }
+
+  test("throwIfInactive: inactiveSince < threshold") {
+    val repo = Repo("repo-cache-alg", "test-2")
+    val commitDate = Timestamp.fromLocalDateTime(LocalDateTime.now())
+    val cache = RepoCache(dummySha1, commitDate, Nil, None, None)
+    val config = RepoConfig(inactivityThreshold = Some(1.day))
+    val data = RepoData(repo, cache, config)
+    val obtained = repoCacheAlg.throwIfInactive(data).runA(MockState.empty).attempt
+    assertIO(obtained, Right(()))
+  }
+
+  test("throwIfInactive: inactiveSince > threshold") {
+    val repo = Repo("repo-cache-alg", "test-3")
+    val cache = RepoCache(dummySha1, Timestamp(0L), Nil, None, None)
+    val config = RepoConfig(inactivityThreshold = Some(1.day))
+    val data = RepoData(repo, cache, config)
+    val obtained = repoCacheAlg
+      .throwIfInactive(data)
+      .runA(MockState.empty)
+      .attemptNarrow[RepositoryInactive]
+      .map(_.leftMap(_.copy(inactiveSince = Duration.Zero)))
+    assertIO(obtained, Left(RepositoryInactive(repo, Duration.Zero, 1.day)))
+  }
 }
diff --git a/modules/core/src/test/scala/org/scalasteward/core/update/PruningAlgTest.scala b/modules/core/src/test/scala/org/scalasteward/core/update/PruningAlgTest.scala
index 3ac0ad3292..f11806153e 100644
--- a/modules/core/src/test/scala/org/scalasteward/core/update/PruningAlgTest.scala
+++ b/modules/core/src/test/scala/org/scalasteward/core/update/PruningAlgTest.scala
@@ -21,6 +21,7 @@ class PruningAlgTest extends FunSuite {
     val Right(repoCache) = decode[RepoCache](
       s"""|{
           |  "sha1": "12def27a837ba6dc9e17406cbbe342fba3527c14",
+          |  "commitDate": 0,
           |  "dependencyInfos": [],
           |  "maybeRepoConfig": {
           |    "pullRequests": {
@@ -79,6 +80,7 @@ class PruningAlgTest extends FunSuite {
     val Right(repoCache) = decode[RepoCache](
       s"""|{
           |  "sha1": "12def27a837ba6dc9e17406cbbe342fba3527c14",
+          |  "commitDate": 0,
           |  "dependencyInfos" : [
           |    {
           |      "value" : [
@@ -218,6 +220,7 @@ class PruningAlgTest extends FunSuite {
     val Right(repoCache) = decode[RepoCache](
       s"""|{
           |  "sha1": "12def27a837ba6dc9e17406cbbe342fba3527c14",
+          |  "commitDate": 0,
           |  "dependencyInfos" : [
           |    {
           |      "value" : [
@@ -330,6 +333,7 @@ class PruningAlgTest extends FunSuite {
     val Right(repoCache) = decode[RepoCache](
       s"""|{
           |  "sha1": "12def27a837ba6dc9e17406cbbe342fba3527c14",
+          |  "commitDate": 0,
           |  "dependencyInfos" : [
           |    {
           |      "value" : [
@@ -441,6 +445,7 @@ class PruningAlgTest extends FunSuite {
     val Right(repoCache) = decode[RepoCache](
       s"""|{
           |  "sha1": "12def27a837ba6dc9e17406cbbe342fba3527c14",
+          |  "commitDate": 0,
           |  "dependencyInfos" : [
           |    {
           |      "value" : [
diff --git a/modules/docs/mdoc/repo-specific-configuration.md b/modules/docs/mdoc/repo-specific-configuration.md
index 005abd09f8..05c07730e8 100644
--- a/modules/docs/mdoc/repo-specific-configuration.md
+++ b/modules/docs/mdoc/repo-specific-configuration.md
@@ -206,6 +206,10 @@ reviewers = [ "username1", "username2" ]
 # If true, Scala Steward will sign off all commits (e.g. `git --signoff`).
 # Default: false
 signoffCommits = true
+
+# Repos whose last commit is older than this threshold are considered
+# inactive and are ignored.
+inactivityThreshold = "90 days"
 """
 
 DocChecker.verifyParsedEqualsEncoded[RepoConfig](input)