--- a/toolkit/components/places/tests/unit/test_telemetry.js
+++ b/toolkit/components/places/tests/unit/test_telemetry.js
@@ -12,17 +12,17 @@ var histograms = {
   PLACES_KEYWORDS_COUNT: val => do_check_eq(val, 1),
   PLACES_SORTED_BOOKMARKS_PERC: val => do_check_eq(val, 100),
   PLACES_TAGGED_BOOKMARKS_PERC: val => do_check_eq(val, 100),
   PLACES_DATABASE_FILESIZE_MB: val => do_check_true(val > 0),
   PLACES_DATABASE_PAGESIZE_B: val => do_check_eq(val, 32768),
   PLACES_DATABASE_SIZE_PER_PAGE_B: val => do_check_true(val > 0),
   PLACES_EXPIRATION_STEPS_TO_CLEAN2: val => do_check_true(val > 1),
   // PLACES_AUTOCOMPLETE_1ST_RESULT_TIME_MS:  val => do_check_true(val > 1),
-  PLACES_IDLE_FRECENCY_DECAY_TIME_MS: val => do_check_true(val > 0),
+  PLACES_IDLE_FRECENCY_DECAY_TIME_MS: val => do_check_true(val >= 0),
   PLACES_IDLE_MAINTENANCE_TIME_MS: val => do_check_true(val > 0),
   // One from the `setItemAnnotation` call; the other from the mobile root.
   // This can be removed along with the anno in bug 1306445.
   PLACES_ANNOS_BOOKMARKS_COUNT: val => do_check_eq(val, 2),
   PLACES_ANNOS_PAGES_COUNT: val => do_check_eq(val, 1),
   PLACES_MAINTENANCE_DAYSFROMLAST: val => do_check_true(val >= 0),
 }