Sick of having Time Machine backup every hour? Want to only have it backup when you want? Simply turn off Time Machine in the preferences. You’ll still be able to use the menu bar drop-down menu to “Back Up Now” whenever you want.
Related: Time Machine volume not dismounting after backup is complete under Lion., New OS Install and Time Machine Backup, Time Machine not Ejecting Time Capsule Icon After Backup, time machine problem, Problems with Time Machine.

That does not work for me. If I do that, then my backup simply does not get updated. Why?
What happens when you try to manual update? Is there an error? Something else? This tip is 2 years old, perhaps something has changed…
You have to go into preferences and turn it back on then use back up now