Adjust Time Machine backup frequency

I managed to get a oldish 3Tb Time Capsule off Carousell for experimenting. It was pretty alright for the first day until I got tired of the hourly loudish HDD spin up.

There must be a way to adjust the hourly backup frequency to every 6 hours. Given this is a oldish EOLed device, I also want to preserve its longevity – as much as i can.

To do so, determine the new backup frequency you want it to be, knowing the backup daemon reads in the backup frequency in seconds.

If you want to adjust to a 12 hour backup, the new number would be 60 seconds * 60 minutes * 12 hours = 43,200

For a 6 hour backup frequency, the new number would be 60 seconds * 60 minutes * 6 hours = 21,600

Next,

1. Go to the macOS terminal app and do the following:
2. Unload the backup daemon using “sudo launchctl unload /System/Library/LaunchDaemons/com.apple.backupd-help.plist“
3. Change frequency on the the following file /System/Library/LaunchDaemons/com.apple.backupd-helper.plist using “sudo nano /System/Library/LaunchDaemons/com.apple.backupd-helper.plist“
4. Look for the line that says “<key>Interval</key><integer>3600</integer>“, change the integer value to the newly calculated value above without the comma.
5. It should read the following with a 12 hour backup frequency “<key>Interval</key><integer>43200</integer>“
6. Save the file with Ctrl-X.
7. Then reload the plist using “sudo launchctl load /System/Library/LaunchDaemons/com.apple.backupd-help.plist“

You will only hear the HDD storage startup only twice a day, and extend the HDD’s life!

PS – The above was verified to work on Mojave.

PPS – You will need to do this for every macOS device.