diff --git a/SVSim.EmulatedEntrypoint/Controllers/AdminController.cs b/SVSim.EmulatedEntrypoint/Controllers/AdminController.cs
index bfbb9eab..dddb7413 100644
--- a/SVSim.EmulatedEntrypoint/Controllers/AdminController.cs
+++ b/SVSim.EmulatedEntrypoint/Controllers/AdminController.cs
@@ -629,7 +629,7 @@ public class AdminController : SVSimController
     private static (string EventKey, string Period)? ResolveAchievementCounter(AchievementCatalogEntry catalog)
     {
         if (string.IsNullOrEmpty(catalog.EventType)) return null;
-        return (catalog.EventType!, GameCalendarService.AllTime);
+        return (catalog.EventType!, GameCalendarPeriods.AllTime);
     }
 
     /// <summary>
diff --git a/SVSim.EmulatedEntrypoint/Controllers/ItemPurchaseController.cs b/SVSim.EmulatedEntrypoint/Controllers/ItemPurchaseController.cs
index e354a312..beefcb46 100644
--- a/SVSim.EmulatedEntrypoint/Controllers/ItemPurchaseController.cs
+++ b/SVSim.EmulatedEntrypoint/Controllers/ItemPurchaseController.cs
@@ -106,7 +106,7 @@ public class ItemPurchaseController : SVSimController
             return BadRequest(new { error = "unknown_purchase" });
 
         var now = _time.GetUtcNow();
-        var period = entry.IsMonthlyReset ? _calendar.MonthKey(now) : GameCalendarService.AllTime;
+        var period = entry.IsMonthlyReset ? _calendar.MonthKey(now) : GameCalendarPeriods.AllTime;
         var key = CounterKey(entry.Id);
 
         var counter = await _db.ViewerEventCounters
@@ -160,11 +160,11 @@ public class ItemPurchaseController : SVSimController
         _ => "debit_type_not_supported",
     };
 
-    private static string CounterKey(int purchaseId) => $"item_purchase:{purchaseId}";
+    private static string CounterKey(int purchaseId) => MissionEventKeys.ItemPurchase(purchaseId);
 
     private static int CounterCount(List<ViewerEventCounter> counters, ItemPurchaseCatalogEntry entry, string monthKey)
     {
-        var period = entry.IsMonthlyReset ? monthKey : GameCalendarService.AllTime;
+        var period = entry.IsMonthlyReset ? monthKey : GameCalendarPeriods.AllTime;
         return counters.FirstOrDefault(c => c.EventKey == CounterKey(entry.Id) && c.Period == period)?.Count ?? 0;
     }
 }
diff --git a/SVSim.EmulatedEntrypoint/Services/GameCalendarService.cs b/SVSim.EmulatedEntrypoint/Services/GameCalendarService.cs
index d7bff2ec..aa8184f8 100644
--- a/SVSim.EmulatedEntrypoint/Services/GameCalendarService.cs
+++ b/SVSim.EmulatedEntrypoint/Services/GameCalendarService.cs
@@ -32,10 +32,14 @@ public interface IGameCalendarService
     IReadOnlyList<string> AllPeriods(DateTimeOffset when);
 }
 
+public static class GameCalendarPeriods
+{
+    /// <summary>The lifetime bucket string — same constant regardless of reset boundary config.</summary>
+    public const string AllTime = "all-time";
+}
+
 public class GameCalendarService : IGameCalendarService
 {
-    public const string AllTime = "all-time";
-
     private readonly IGameConfigService _config;
 
     public GameCalendarService(IGameConfigService config)
@@ -73,7 +77,7 @@ public class GameCalendarService : IGameCalendarService
 
     public IReadOnlyList<string> AllPeriods(DateTimeOffset when) => new[]
     {
-        DayKey(when), WeekKey(when), MonthKey(when), AllTime,
+        DayKey(when), WeekKey(when), MonthKey(when), GameCalendarPeriods.AllTime,
     };
 
     private DateTime MostRecentBoundary(DateTime nowUtc)
diff --git a/SVSim.EmulatedEntrypoint/Services/MissionAssembler.cs b/SVSim.EmulatedEntrypoint/Services/MissionAssembler.cs
index d000b07b..7bb6102f 100644
--- a/SVSim.EmulatedEntrypoint/Services/MissionAssembler.cs
+++ b/SVSim.EmulatedEntrypoint/Services/MissionAssembler.cs
@@ -107,7 +107,7 @@ public sealed class MissionAssembler : IMissionAssembler
         foreach (var a in viewerAchievements.OrderBy(a => a.AchievementType))
         {
             if (!achievementCatalogByKey.TryGetValue((a.AchievementType, a.Level), out var catalog)) continue;
-            int total = catalog.EventType is null ? 0 : GetCounter(catalog.EventType, GameCalendarService.AllTime);
+            int total = catalog.EventType is null ? 0 : GetCounter(catalog.EventType, GameCalendarPeriods.AllTime);
             int maxLevel = maxLevelByType.TryGetValue(a.AchievementType, out var ml) ? ml : a.Level;
             dto.UserAchievementList.Add(new UserAchievementDto
             {
diff --git a/SVSim.EmulatedEntrypoint/Services/MissionProgressService.cs b/SVSim.EmulatedEntrypoint/Services/MissionProgressService.cs
index 0d340f06..8e729c30 100644
--- a/SVSim.EmulatedEntrypoint/Services/MissionProgressService.cs
+++ b/SVSim.EmulatedEntrypoint/Services/MissionProgressService.cs
@@ -53,7 +53,7 @@ public sealed class MissionProgressService : IMissionProgressService
                 var atLevel = catalogRows.FirstOrDefault(r => r.Level == viewerRow.Level);
                 if (atLevel is null || atLevel.EventType is null) continue;
 
-                var count = await _viewerRepo.GetCounterAsync(viewerId, atLevel.EventType, GameCalendarService.AllTime, ct);
+                var count = await _viewerRepo.GetCounterAsync(viewerId, atLevel.EventType, GameCalendarPeriods.AllTime, ct);
                 if (count >= atLevel.RequireNumber && viewerRow.AchievementStatus == 0)
                 {
                     viewerRow.AchievementStatus = 1;
diff --git a/SVSim.UnitTests/Services/GameCalendarServiceTests.cs b/SVSim.UnitTests/Services/GameCalendarServiceTests.cs
index b4c8a849..7430a2a1 100644
--- a/SVSim.UnitTests/Services/GameCalendarServiceTests.cs
+++ b/SVSim.UnitTests/Services/GameCalendarServiceTests.cs
@@ -122,7 +122,7 @@ public class GameCalendarServiceTests
         var svc = NewService(0);
         var periods = svc.AllPeriods(Utc(2026, 5, 27, 12, 0, 0));
         Assert.That(periods, Is.EquivalentTo(new[] {
-            "day:2026-05-27", "week:2026-W22", "month:2026-05", GameCalendarService.AllTime,
+            "day:2026-05-27", "week:2026-W22", "month:2026-05", GameCalendarPeriods.AllTime,
         }));
     }
 }