diff --git a/src/SQLInsight.Agent/Configuration/AgentRequestService.cs b/src/SQLInsight.Agent/Configuration/AgentRequestService.cs
index 6f5d4f8..297fe86 100644
--- a/src/SQLInsight.Agent/Configuration/AgentRequestService.cs
+++ b/src/SQLInsight.Agent/Configuration/AgentRequestService.cs
@@ -41,6 +41,11 @@ public sealed partial class AgentRequestService(
 
     public static readonly TimeSpan RequestTimeout = TimeSpan.FromMinutes(2);
 
+    /// <summary>The least time between two routine discoveries of one instance, also when the last one could not be stored.</summary>
+    public static readonly TimeSpan RoutineRetry = TimeSpan.FromMinutes(15);
+
+    private readonly Dictionary<int, DateTimeOffset> _routineAttempts = [];
+
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
         await readiness.Ready.WaitAsync(stoppingToken).ConfigureAwait(false);
@@ -172,8 +177,11 @@ public sealed partial class AgentRequestService(
     /// <summary>The routine discovery of the active instance that waited longest, if one is due.</summary>
     private async Task RefreshOneAsync(DateTimeOffset now, CancellationToken cancellationToken)
     {
+        // Also waits on the agent's own last attempt: if storing the result fails (the repository), LastDiscoveryAt is
+        // not set, and without this the same instance would be listed again every round (every 2 seconds).
         var due = (await repository.GetConfiguredInstancesAsync(cancellationToken).ConfigureAwait(false))
             .Where(i => !i.Paused && i.CredentialError is null && (i.LastDiscoveryAt is null || now.UtcDateTime - i.LastDiscoveryAt.Value >= DiscoveryInterval))
+            .Where(i => !_routineAttempts.TryGetValue(i.ConfiguredInstanceId, out var attempted) || now - attempted >= RoutineRetry)
             .OrderBy(i => i.LastDiscoveryAt ?? DateTime.MinValue)
             .FirstOrDefault();
         if (due is null)
@@ -181,6 +189,7 @@ public sealed partial class AgentRequestService(
             return;
         }
 
+        _routineAttempts[due.ConfiguredInstanceId] = now;
         using var timeout = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
         timeout.CancelAfter(RequestTimeout);
         try