1. Firefox has to be running to be able to check for updates. 2. There's no "timer" that can be set to schedule updates for Firefox or addins. Firefox looks for addon updates as part of the launch procedure the first time it is used each day. The Firefox program update check is done a few minutes later. The actual time the update check is performed, is kept track of internally so that Firefox only does the check roughly once every 24 hours. "Time" is in the UnixEpoch format, the number of seconds that have elapsed since Jan 1, 1970 GMT.