By default, Time Machine performs a backup every 3600 seconds. You can change this setting with Terminal commands. This example sets it to 9600 seconds.

1. Launch Terminal from the Utilities folder.

2. Type the following and press Return or Enter on your keyboard.

sudo defaults write /System/Library/LaunchDaemons/com.apple.backupd-auto StartInterval -int 9600   

Now Time Machine will backup your items every 9600 seconds. You can change the 9600 value to whatever you like.