I bought a new drive and am partitioning it to limit how much Time Machine uses. How big should I make the partition?

Short Answer: I’d say around 25% larger than what your computer’s hard drive size.

Backing up is SO important, and Apple’s new operating system includes a very powerful and easy to use application called Time Machine. All you need is an external drive to backup to, and you’re good to go!

To understand how much space you need, you should know how Time Machine works. The first time you backup, it backs up your whole hard drive. From then on when it backs up your computer, it only backs up what you’ve changed. Once your backup drive is full, you can set Time Machine to delete old backups.

My lappie’s drive is 120GB and my 160GB backup drive is EASILY big enough!

If you aren’t deleting/adding tons of files on a daily, or even weekly basis, a backup drive that’s slightly bigger than your hard drive, like 25%, is more than enough. That being said, hard drive space is CHEAP, and you’ll never wish you bought something smaller — A 500GB USB 2.0 drive from Future Shop is only $119!