Mac's don't need defragging as OS X automatically writes 2Gb or below sized files to one contiguous space on the drive. There are certain cases where's it's needed to free up a large spaces on the drive, but not something everyone has to do.
Far as other Mac maintainence, there really isn't any except to backup one's files regularly. Keeping Software Updated and run a web browser check to make sure the plug-ins are current.
OnyX – Mac Cleaner Software. This is one of the best free Mac cleaner software out there. First, it’s a free tool and it has lots of positive reviews as well. This Free Mac cleaner is a multifunction utility tool that can help you clean up the browsing catch, system junk and optimize the speed of your Mac. BullGuard Antivirus (Mac) MSRP: $23.99 per month. Best Prices Today: $23.99 at Bullguard. Bullguard for Mac is unbelievably simple virus protection—perhaps too simple. If you already own a.
For Safari and Flash, this check is more accurate
Most of those cleaning programs are junk, especially MacKeeper.
If your friend got onto your computer and visited a bunch of adult sites, then I would recommend something like OnyX, doing ALL the cleaning and maintenance aspects and rebooting, perhaps followed by a Disk Utility Erase free space.
CCleaner beta is out for OS X, used on PC's and combines cleaning and scrubbing of the drive if setup correctly.
Mac Computer Cleaner Software
If your interested in performance, read my post here
The Best Free Mac Cleaner
Oct 1, 2011 12:37 AM