I have been struggling to resolve this issue for over a month now. Every so often (I have not determined that the issue arises upon a restart of the server or after a specific number of days), I receive an "Error 1069: The service did not start due to a logon failure" when trying to start the SharePoint 2010 Timer service.
I have seen many solutions online to reset the password of the spfarm account, change the password for the service, and change the password under the SP Central Administration. Following these steps will allow me to restart the service and it will run just fine for an unspecific amount of time. But after a few days (and possibly a server restart from updates), the SP 2010 Timer service will not restart with this same logon failure.
I'm assuming that the issue arises when SharePoint changes the password of the managed accounts and the password change is not reflected in AD.