I think your are talking about disk optimization. Well the current OS X doesn't really need it. In OS X the hard drive is "Journaled". However you will need to do some preventative maintenance to keep OS X running like new. OS X is based on BSD Unix and Unix loves it's file permissions. So every Os X software developer thinks their program should be king on your computer and those programs will mess with file permissions. In OS X all you need to do (about every two weeks or after large software installs) is go to the application in /Applications/Utilties/ and open the program Disk Utility and run the "Repair Permissions" part of the program.
Also because OS X is based on BSD Unix, that portion keeps logs on most every function of your Mac. You can see these logs (also very good for trouble shooting) by going to /Applications/Utilties/ and launch the program Console. As you can see there are many logs of almost every flavor. No these logs can grow very large over time. So way back, before most of us were born, Unix had scripts put in that would archive and maintain the logs. These Unix scripts are called cron. They are present in a Mac and run around 3 o'clock in the local morning time for the user's machine. The problem arises that most all Mac users "sleep" their Macs at that time, preventing cron from running the scripts. Luckily third party developer (many of them) let you run this cron scripts (with a nice OS X application) at your leisure. You can find those programs by going to either MacUpdate or VersionTracker and do a search on cron. You will find numerous programs that will let you run the cron jobs. Personally I like one trick, small programs in running cron so I use a simple program to run the cron jobs, that is point and click, called MacJanitor.
Lastly OS X is not immune to problems so a good disk fix program should be in your arsenal. I my opinion (as many others) the best disk maintenance program for OS X is called Disk Warrior. It has saved my butt more than once.
Now for the warning about one program, that has been discontinued, that will destroy any OS X machine. Stay far away from Norton for Mac.
Also, you may want to know a lot more about your mac. I recommend a good book and the one that I have in mind is David Pogue's Mac OS X: The Missing Manual, Tiger Ed (Missing Manual). It is most every book store and online. It will help you become a proficient OS x user and ease your move to the Mac.
Mac Pro Dual 2.8 Quad (2nd gen), 14G Ram, Two DVD-RW Drives, OS X 10.9.1
2006 Mac Book Pro 2.16 (first Gen) OS X 10.7.5
2TB Time Capsule, 2 TB
32G iPhone 4S Black, iPad (3rd Gen) 32G Black