Mac OS X only: Freeware application TimeMachineEditor changes Time Machine’s default once-per-hour backup interval to a more flexible schedule. Similar to previously mentioned TimeMachineScheduler, TME offers more advanced intervals and exact scheduling. If you’re noticing significant slowdowns on your Mac whenever Time Machine runs its hourly backup (which isn’t uncommon), extending your backup intervals or pushing the backup to a once-a-day affair with the freeware TimeMachineEditor should help.