--- a/services/common/remote-settings.js
+++ b/services/common/remote-settings.js
@@ -119,21 +119,21 @@ async function fetchLatestChanges(url, l
   }
 
   return {changes, currentEtag, serverTimeMillis, backoffSeconds};
 }
 
 
 class RemoteSettingsClient {
 
-  constructor(collectionName, { lastCheckTimePref, bucketName, signerName }) {
+  constructor(collectionName, { bucketName, signerName, lastCheckTimePref }) {
     this.collectionName = collectionName;
-    this.lastCheckTimePref = lastCheckTimePref;
     this.bucketName = bucketName;
     this.signerName = signerName;
+    this._lastCheckTimePref = lastCheckTimePref;
 
     this._callbacks = new Map();
     this._callbacks.set("sync", []);
 
     this._kinto = null;
   }
 
   get identifier() {
@@ -141,16 +141,20 @@ class RemoteSettingsClient {
   }
 
   get filename() {
     // Replace slash by OS specific path separator (eg. Windows)
     const identifier = OS.Path.join(...this.identifier.split("/"));
     return `${identifier}.json`;
   }
 
+  get lastCheckTimePref() {
+    return this._lastCheckTimePref || `services.settings.${this.bucketName}.${this.collectionName}.last_check`;
+  }
+
   on(event, callback) {
     if (!this._callbacks.has(event)) {
       throw new Error(`Unknown event type ${event}`);
     }
     this._callbacks.get(event).push(callback);
   }
 
   /**
@@ -403,22 +407,16 @@ class RemoteSettingsClient {
   }
 
   /**
    * Save last time server was checked in users prefs.
    *
    * @param {Date} serverTime   the current date return by server.
    */
   _updateLastCheck(serverTime) {
-    if (!this.lastCheckTimePref) {
-      // If not set (default), it is not necessary to store the last check timestamp.
-      return;
-    }
-    // Storing the last check time is mainly a matter of retro-compatibility with
-    // the blocklists clients.
     const checkedServerTimeInSeconds = Math.round(serverTime / 1000);
     Services.prefs.setIntPref(this.lastCheckTimePref, checkedServerTimeInSeconds);
   }
 }
 
 
 function remoteSettingsFunction() {
   const _clients = new Map();

--- a/services/common/tests/unit/test_blocklist_clients.js
+++ b/services/common/tests/unit/test_blocklist_clients.js
@@ -122,16 +122,19 @@ add_task(async function test_list_is_wri
     const content = await readJSON(profFile.path);
     equal(content.data[0].blockID, testData[testData.length - 1]);
   }
 });
 add_task(clear_state);
 
 add_task(async function test_current_server_time_is_saved_in_pref() {
   for (let {client} of gBlocklistClients) {
+    // The lastCheckTimePref was customized:
+    ok(/services\.blocklist\.(\w+)\.checked/.test(client.lastCheckTimePref), client.lastCheckTimePref);
+
     const serverTime = Date.now();
     await client.maybeSync(2000, serverTime);
     const after = Services.prefs.getIntPref(client.lastCheckTimePref);
     equal(after, Math.round(serverTime / 1000));
   }
 });
 add_task(clear_state);
 

--- a/services/common/tests/unit/test_remote_settings.js
+++ b/services/common/tests/unit/test_remote_settings.js
@@ -74,16 +74,25 @@ add_task(async function test_records_obt
 
   // Open the collection, verify it's been populated:
   // Our test data has a single record; it should be in the local collection
   const list = await client.get();
   equal(list.length, 1);
 });
 add_task(clear_state);
 
+add_task(async function test_current_server_time_is_saved_in_pref() {
+  const serverTime = Date.now();
+  await client.maybeSync(2000, serverTime);
+  equal(client.lastCheckTimePref, "services.settings.main.password-fields.last_check");
+  const after = Services.prefs.getIntPref(client.lastCheckTimePref);
+  equal(after, Math.round(serverTime / 1000));
+});
+add_task(clear_state);
+
 add_task(async function test_records_changes_are_overwritten_by_server_changes() {
   // Create some local conflicting data, and make sure it syncs without error.
   const collection = await client.openCollection();
   await collection.create({
     "website": "",
     "id": "9d500963-d80e-3a91-6e74-66f3811b99cc"
   }, { useRecordId: true });