Another related tip if you are short of disk space is to periodically delete some of the archived log files. Unless you have a need to maintain every tidbit of information about a computer's activity, you can probably delete months-old log files without any worries. Log files are useful for troubleshooting problems and can also be used to investigate activity that has occurred on a Mac. However, if you've never looked at a log file, aren't experiencing any problems, and the file is months old, chances are you aren't ever going to need to look at it. Given that some log files can get quite big, this can be one way to put your hard drive on a diet.
10. Restart periodically
One of the simplest ways to keep your Mac running well is to periodically restart it. Although there is no need to shut down Mac OS X on a nightly basis (many users report running Macs for months on end without restarting), restarting a Mac every couple weeks can be helpful both in a general sense and if you are experiencing any problems.
When a Mac boots, several different routines are called as part of the start-up sequence, including a basic file-system check (the Unix fsck tool) that verifies some of the directory structures on the hard drive and a clearing of any temporary files stored in the Unix /tmp directory. Rebooting also causes the Mac to run through its power on hardware tests and reinitialize its connection to any built-in hardware.
Ryan Faas is a frequent Computerworld contributor specializing in Mac and multiplatform network issues. Find more about him at RyanFaas.com.