For a lot of regular Time Machine users, hourly backups are not completely necessary. Unfortunately, there is not an option to change the time between these increments within Time Machine, so it is usually just accepted by the user. If you have added any large files to your computer in the past hour, backing up these newly added/altered files can take some time, and ultimately slow down your computer’s performance.
Obviously, one work-around is to eject the hard drive being used with Time Machine, and then plug it back in when you would like a backup performed. This can lead to some issues, however, like if you forget to mount the drive right before your internal hard drive crashes and possibly lose all that unbacked-up data.
A much more efficient and convenient solution is available, however. It is a little utility called TimeMachineEditor. With this utility, the user can easily schedule his or her backups, or just set a longer interval between them. I personally prefer to do daily backups late at night, when I’m finished using my computer.
TimeMachineEditor is a free download and easy install for Macs running 10.5, 10.6, or 10.7 (no word from the developer on 10.8 compatibility yet). It’s available here.