Annoyed when Time Machine kicks on ALL THE TIME? Well, maybe it’s not all the time, but it is every hour you have a hard drive plugged in or Time Machine set to run. That’s too often for me, so I decided to see what I could do to change it.
1) Go to Macintosh HD > System > Library > LaunchDaemons
2) Open com.apple.backupd-auto.plist in Text Edit (or other text editor)
4) Change the 3600 to the number of your choice
Note: You must be the system administrator of your Mac for this to work as written.