The backup schedule of Time Machine!
A great tip submitted by Dominic P. Tremblay: The backup schedule of Time Machine! I have to admit, looking at Time Machine's preferences, it is somewhat disappointing. I think Time Machine is really great, but its weakness is that it is not customizable in the slightest. Some third-party applications have started cropping up, changing that. There is a great one called "TimeMachineScheduler" that lets you change how much time there is between backups. It will let you set anything between 1 to 12 hours. You can download or get more info about TimeMachineScheduler here on the developer's site. Thanks for the tip Dominic!