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.
CCleaner for Mac! Clean up your Mac and keep your browsing behaviour private with CCleaner, the world's favourite computer cleaning tool. Match Edited Photos: By default, Duplicate Cleaner for iPhoto won’t match photos if one has been modified. To change this, select Duplicate Cleaner for iPhoto Preferences and check this box.
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.
For Safari and Flash, this check is more accurate
Best Mac Duplicate Photo Cleaner
Best Mac Photo Cleaner
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.
If your interested in performance, read my post here
Oct 1, 2011 12:37 AM