diff --git a/frontend/src/components/Common/ConnectionNotice.tsx b/frontend/src/components/Common/ConnectionNotice.tsx
index f4675f7..03954d2 100644
--- a/frontend/src/components/Common/ConnectionNotice.tsx
+++ b/frontend/src/components/Common/ConnectionNotice.tsx
@@ -1,9 +1,9 @@
 import { useEffect, useSyncExternalStore } from "react"
 
-import { ago } from "@/components/Health/queries"
 import { connectionStore } from "@/lib/connectionStore"
 import { dismiss, notify } from "@/lib/notificationStore"
 import { isPortal } from "@/lib/portal"
+import { ago } from "@/lib/utils"
 
 /** One card, replaced in place, rather than one per poll that confirms it. */
 const ID = "connection-offline"
diff --git a/frontend/src/components/Flow/EdgeInspector.tsx b/frontend/src/components/Flow/EdgeInspector.tsx
index 02d1a60..6c2ec0f 100644
--- a/frontend/src/components/Flow/EdgeInspector.tsx
+++ b/frontend/src/components/Flow/EdgeInspector.tsx
@@ -6,6 +6,7 @@ import { Marquee } from "@/components/Common/Marquee"
 import { Button } from "@/components/ui/button"
 import { Popover, PopoverAnchor, PopoverContent } from "@/components/ui/popover"
 import useCustomToast from "@/hooks/useCustomToast"
+import { ago } from "@/lib/utils"
 import { displayName } from "./deriveEdges"
 import { useLiveValue } from "./liveStore"
 import { MessageSparkline } from "./MessageSparkline"
@@ -13,11 +14,7 @@ import { ValuePreview } from "./ValuePreview"
 
 export function relativeTime(ts: number | null | undefined): string {
   if (!ts) return "not seen yet"
-  const seconds = Math.max(0, Math.round(Date.now() / 1000 - ts))
-  if (seconds < 5) return "just now"
-  if (seconds < 60) return `${seconds}s ago`
-  if (seconds < 3600) return `${Math.round(seconds / 60)}m ago`
-  return `${Math.round(seconds / 3600)}h ago`
+  return Date.now() / 1000 - ts < 5 ? "just now" : ago(ts)
 }
 
 /**
diff --git a/frontend/src/components/Health/HealthActivity.tsx b/frontend/src/components/Health/HealthActivity.tsx
index 2b4c0be..6386111 100644
--- a/frontend/src/components/Health/HealthActivity.tsx
+++ b/frontend/src/components/Health/HealthActivity.tsx
@@ -8,9 +8,8 @@ import { UplotChart } from "@/components/Common/UplotChart"
 import { useEngineEventMinute } from "@/components/Flow/liveStore"
 import { PANEL_SECTION } from "@/components/Flow/SidePanel"
 import { Button } from "@/components/ui/button"
-import { cn, dur, si } from "@/lib/utils"
+import { ago, cn, dur, si } from "@/lib/utils"
 import {
-  ago,
   auditQueryOptions,
   CARD,
   clock,
@@ -358,7 +357,7 @@ export function HealthActivity({ range }: { range: Range }) {
                   <span className="w-20 shrink-0 whitespace-nowrap text-right text-muted-foreground">
                     {dur(run.duration_ms)}
                   </span>
-                  <span className="w-16 shrink-0 text-right text-xs text-muted-foreground">
+                  <span className="w-24 shrink-0 whitespace-nowrap text-right text-xs text-muted-foreground">
                     {ago(run.started_at)}
                   </span>
                 </div>
diff --git a/frontend/src/components/Health/HealthOverview.tsx b/frontend/src/components/Health/HealthOverview.tsx
index 61e2b06..81c5571 100644
--- a/frontend/src/components/Health/HealthOverview.tsx
+++ b/frontend/src/components/Health/HealthOverview.tsx
@@ -5,9 +5,8 @@ import { type Range, RangePicker } from "@/components/Common/RangePicker"
 import { PANEL_SECTION } from "@/components/Flow/SidePanel"
 import { runOverviewQueryOptions } from "@/components/Runs/queries"
 import { Badge } from "@/components/ui/badge"
-import { cn, dur, si } from "@/lib/utils"
+import { ago, cn, dur, si } from "@/lib/utils"
 import {
-  ago,
   CARD,
   failuresQueryOptions,
   flowRollupsQueryOptions,
diff --git a/frontend/src/components/Health/queries.ts b/frontend/src/components/Health/queries.ts
index fecc76b..81c269b 100644
--- a/frontend/src/components/Health/queries.ts
+++ b/frontend/src/components/Health/queries.ts
@@ -122,17 +122,6 @@ export const deadLetterQueryOptions = () => ({
   refetchInterval: REFRESH,
 })
 
-/** How long ago something happened, in the coarsest unit that still says it. */
-export function ago(ts: string | number | null | undefined): string {
-  if (!ts) return "—"
-  const stamp = typeof ts === "number" ? ts * 1000 : Date.parse(ts)
-  const seconds = Math.max(0, (Date.now() - stamp) / 1000)
-  if (seconds < 90) return `${Math.round(seconds)}s ago`
-  if (seconds < 5400) return `${Math.round(seconds / 60)}m ago`
-  if (seconds < 172800) return `${Math.round(seconds / 3600)}h ago`
-  return `${Math.round(seconds / 86400)}d ago`
-}
-
 /**
  * The minute a timestamp belongs to, as unix seconds.
  *
diff --git a/frontend/src/components/Runs/RunDetail.tsx b/frontend/src/components/Runs/RunDetail.tsx
index 6a8b5c4..a26b8b0 100644
--- a/frontend/src/components/Runs/RunDetail.tsx
+++ b/frontend/src/components/Runs/RunDetail.tsx
@@ -5,7 +5,6 @@ import { useState } from "react"
 
 import type { ArtifactRow, RunNodeRow } from "@/client"
 import { ValuePreview } from "@/components/Flow/ValuePreview"
-import { ago } from "@/components/Health/queries"
 import { Button } from "@/components/ui/button"
 import { Skeleton } from "@/components/ui/skeleton"
 import {
@@ -17,7 +16,7 @@ import {
   TableRow,
 } from "@/components/ui/table"
 import useCustomToast from "@/hooks/useCustomToast"
-import { cn, dur, si } from "@/lib/utils"
+import { ago, cn, dur, si } from "@/lib/utils"
 import { MetricPicker, RunMetricChart, useMetricNames } from "./MetricChart"
 import { OpenInDashboard } from "./OpenInDashboard"
 import {
diff --git a/frontend/src/components/Runs/RunsScreen.tsx b/frontend/src/components/Runs/RunsScreen.tsx
index cdd4c95..18037c6 100644
--- a/frontend/src/components/Runs/RunsScreen.tsx
+++ b/frontend/src/components/Runs/RunsScreen.tsx
@@ -39,7 +39,7 @@ import {
   TableHeader,
   TableRow,
 } from "@/components/ui/table"
-import { cn, dur } from "@/lib/utils"
+import { ago, cn, dur } from "@/lib/utils"
 import {
   AxisPicker,
   MetricPicker,
@@ -425,12 +425,6 @@ function ParamValue({ value }: { value: unknown }) {
   )
 }
 
-/** How long ago a moment was, in `dur`'s units so a row's two times agree. */
-function since(ts: unknown): string {
-  if (!ts) return "—"
-  return `${dur(Date.now() - Date.parse(String(ts)))} ago`
-}
-
 function RunsTable({
   runs,
   search,
@@ -611,7 +605,7 @@ function RunsTable({
                 `${dur(run.duration_ms)} ago`
               ) : (
                 <>
-                  {since(run.created_at)}
+                  {ago(String(run.created_at ?? ""))}
                   <span className="px-1.5 text-border">|</span>
                   <span>{run.duration_ms ? dur(run.duration_ms) : "—"}</span>
                 </>
diff --git a/frontend/src/lib/utils.ts b/frontend/src/lib/utils.ts
index 3969708..5608c7d 100644
--- a/frontend/src/lib/utils.ts
+++ b/frontend/src/lib/utils.ts
@@ -81,3 +81,13 @@ export function dur(ms: number, digits = 3): string {
   ]
   return `${Number((rounded / factor).toPrecision(digits))} ${unit}`
 }
+
+/**
+ * How long ago a moment was, in `dur`'s notation: "4.52 min ago". A number is
+ * unix seconds, a string an ISO timestamp.
+ */
+export function ago(ts: string | number | null | undefined): string {
+  if (!ts) return "—"
+  const stamp = typeof ts === "number" ? ts * 1000 : Date.parse(ts)
+  return `${dur(Math.max(0, Date.now() - stamp))} ago`
+}
diff --git a/frontend/src/routes/_layout/workers.tsx b/frontend/src/routes/_layout/workers.tsx
index 7abb438..c5a73d1 100644
--- a/frontend/src/routes/_layout/workers.tsx
+++ b/frontend/src/routes/_layout/workers.tsx
@@ -23,6 +23,7 @@ import { Input } from "@/components/ui/input"
 import { Label } from "@/components/ui/label"
 import useAuth from "@/hooks/useAuth"
 import useCustomToast from "@/hooks/useCustomToast"
+import { ago } from "@/lib/utils"
 import { handleError } from "@/utils"
 
 export const Route = createFileRoute("/_layout/workers")({
@@ -40,13 +41,6 @@ const emptyFlavor = { name: "", cpus: 1, gpus: 0, ram: 2048, description: "" }
 /** Fresh enough to watch a node take a machine, slow enough to be free. */
 const REFETCH_MS = 5000
 
-function ago(seconds: number): string {
-  const since = Date.now() / 1000 - seconds
-  if (since < 60) return `${Math.max(0, Math.round(since))}s ago`
-  if (since < 3600) return `${Math.round(since / 60)}m ago`
-  return `${Math.round(since / 3600)}h ago`
-}
-
 type Level = { total: number; free: number }
 
 /** "cpu 2/18" — what is in use, out of what there is. */
@@ -203,7 +197,7 @@ function Attached() {
               {worker.protocol}
             </span>
             <span>
-              {worker.behind ? "refused" : "seen"} {ago(worker.last_seen ?? 0)}
+              {worker.behind ? "refused" : "seen"} {ago(worker.last_seen)}
             </span>
           </span>
         </div>
diff --git a/frontend/src/utils.ts b/frontend/src/utils.ts
index a7eb1eb..eb5f66c 100644
--- a/frontend/src/utils.ts
+++ b/frontend/src/utils.ts
@@ -1,7 +1,7 @@
 import { AxiosError } from "axios"
 import type { ApiError } from "./client"
-import { ago } from "./components/Health/queries"
 import { offlineDetail } from "./lib/connectionStore"
+import { ago } from "./lib/utils"
 
 function extractErrorMessage(err: ApiError): string {
   // An unreachable instance is not a rejected action: say plainly that