Why should you have to remember to clean up your Mac every day, every week, and every month? Shouldn't a computer be able to remember for you?
Macaroni is a tool which handles regular maintenance for Mac OS X, including the Mac OS X repair privileges process as well as Unix-style maintenance. Without Macaroni, some of these tasks normally run in the middle of the night, and don't get run unless you leave your Mac on all night. Others don't run automatically at all, and won't happen unless you remember when they're due.
Macaroni remembers the schedule for you!