diff --git a/README.md b/README.md
index fe40038..5654819 100644
--- a/README.md
+++ b/README.md
@@ -788,7 +788,8 @@ subsequent runs, existing originals are skipped. If a download fails, the error
 is logged and the backup continues with the next file. The exit code is non-zero
 if any files failed. `quak backup` opens its library with the thumbnail and
 originals precache off, so the only file content it fetches is the originals the
-backup stores.
+backup stores. It also opens it with no background timer, so it asks the server
+for changes only as it starts, not again while it downloads.
 
 With `--verify`, or `lib.backup({ verify: true })`, a run also hashes each
 original already at its save path the way a download is checked (see "On-disk
@@ -869,7 +870,7 @@ background, so an unreachable server does not block opening.
 | `client`                 | required                                           | the account client (a `Client`, or any `LibraryClient`)              |
 | `cacheDirectory`         | `quak/<userID>` under the per-user cache directory | where `metadata.json` and the content cache live                     |
 | `downloadDirectory`      | `photos` in the working directory                  | root of the save paths; an original stored there counts as cached    |
-| `refreshIntervalSeconds` | `3`                                                | background refresh cadence                                           |
+| `refreshIntervalSeconds` | `3`                                                | background refresh cadence; `Infinity` for no background timer       |
 | `precacheThumbnails`     | `true`                                             | prefetch every thumbnail, newest first                               |
 | `precacheOriginals`      | `true`                                             | prefetch the favorites album and the latest-window originals         |
 | `precacheOriginalsDays`  | `7`                                                | length in days of that latest window                                 |
diff --git a/TODO.md b/TODO.md
index 87de288..25a6bfb 100644
--- a/TODO.md
+++ b/TODO.md
@@ -25,6 +25,13 @@ declares one.
 
 # Completed Steps
 
+- 2026-10-14: `quak backup` no longer asks the server for changes every 3
+  seconds while it runs (issue 183). It opens its library with
+  `refreshIntervalSeconds: Infinity`, which the library now takes as no
+  background timer, so the backup refreshes only as it starts and no timed
+  refresh starts another ML data pass during the run. A test holds a backup's
+  download open while two hours pass and counts its `/collections/v2` requests.
+
 - 2026-10-14: `test/cli/backup-end-to-end.test.ts` runs `quak backup` as cron
   does (issue 186): `backupCommand` and `run`, the real `loadSession` reading a
   session saved after logging in, and every request answered by a fake of the
diff --git a/src/cli-commands.ts b/src/cli-commands.ts
index 5f8b0b6..154c180 100644
--- a/src/cli-commands.ts
+++ b/src/cli-commands.ts
@@ -427,10 +427,13 @@ export const backupCommand = async (
     try {
         // The precache is off: the backup fetches what it needs, and must not
         // also fill the cache with every thumbnail and the recent originals.
+        // No refresh starts on a timer: the backup lists its files once, from
+        // the refresh it waits for, and can run for hours.
         const lib = await Library.open({
             client,
             downloadDirectory: dir,
             cacheDirectory: ctx.cacheDir,
+            refreshIntervalSeconds: Infinity,
             precacheThumbnails: false,
             precacheOriginals: false,
         });
diff --git a/src/library/index.ts b/src/library/index.ts
index 489dd88..080020b 100644
--- a/src/library/index.ts
+++ b/src/library/index.ts
@@ -179,6 +179,9 @@ export interface LibraryOptions {
     // directory at open. The content cache treats an original already stored
     // at its save path as present.
     downloadDirectory?: string;
+    // How long after one refresh ends the background timer starts the next.
+    // `Infinity` starts none: the library then refreshes only as it opens and
+    // when `fresh()` or `backup()` asks.
     refreshIntervalSeconds?: number;
     onProgress?: RefreshProgressCallback;
     // The bounded request pools (issue #45), shared by the ML-data fetch (the
@@ -627,7 +630,8 @@ export class Library {
     }
 
     private scheduleNext(): void {
-        if (this.closed) return;
+        // `setTimeout` would turn an infinite delay into 1 ms.
+        if (this.closed || this.intervalMs === Infinity) return;
         this.timer = setTimeout(() => {
             void this.runRefresh().then(() => this.scheduleNext());
         }, this.intervalMs);