[JazzCatDRP]

My apologies if this should be in the Mac OS X forum. Couldn't decide which it should go under. Anywhos, my time machine backup drive is slowly reporting fewer and fewer gigabytes in use. It's less than half full, but curiously the drive's used space is going down. Is this normal?

[legacyb4]

How frequently are files that are being backed up being changed? Don't forget that Time Machine doesn't back up individual files each time it runs; only the files that have changed will be (in a nutshell explanation...)

[JazzCatDRP]

Yeah, I know it only adds the changed files...I just can't figure out why it's used space is actually getting smaller overall

[alex_kac]

Because TM deletes old backups. If you have a backup every hour, and a week from now TM deletes all backups from 0:00 to 23:00 and keeps the last one.