11-03-2009, 10:38 PM
TM is great as insurance for recently lost items or for taking a Mac back to just before a problematic OS update with the help of the install disks.
It is NOT a long term back up option.
The info is in System prefs:
TM Keeps Hourly backups of 24 hours. Daily backups for the past month. Weekly backups for all the previous months.
The oldest backups get deleted when your drive becomes full.
If you leave a month or so between backups TM will have to run a completely new Backup rather than the usual small updates with links. It's made for hourly backups although you might get away with weekly ones.
Best not to muck around with TM backups in Finder, use the App.
Put the TM icon on the Menu bar from System prefs ~ right click it holding down the option (alt) key and you will be able to Browse other TM Disks that are not immediately obvious.
If you change too much TM will decide that you are using a New Mac and will start again..