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.
Question: Q: Which is the best Mac system cleaner app? Check the System Memory tab at the bottom of Activity Monitor to see if you have excessive 'page outs', a sign that you may benefit from more RAM. Check if you are running any poor Mac anti-virus programs as they may take large resouces. Feb 23, 2016 Make your Mac run faster with this free app from the app store. Memory Clean will display how much available memory you have on your Mac. https://gmgogow.weebly.com/blog/download-facebook-for-android-version-442.
Far as other Mac maintainence, there really isn't any except to backup one's files regularly. Avery designpro 5.4 limited edition download. Keeping Software Updated and run a web browser check to make sure the plug-ins are current.
Dmg liquid for dogs. 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.
Free Memory Cleaner
![Memory Memory](/uploads/1/3/3/8/133870356/153332089.jpg)
Mac Memory Cleaner
CCleaner beta is out for OS X, used on PC's and combines cleaning and scrubbing of the drive if setup correctly.
![Mac Memory Cleaner Review Mac Memory Cleaner Review](/uploads/1/3/3/8/133870356/181467780.jpg)
If your interested in performance, read my post here