It's not necessary, on Windows or Mac OS X. Disk Cleanup is a complete waste of time. It basically just empties the trash and deletes a few non-essential files. None of which has any impact on performance whatsoever.
By and large, computers do not require day to day maintenance. That is all taken care of behind the scenes automatically. Doesn't matter if it's Windows, Linux, Mac OS X, or something else. They require very little intervention on our part these days, but that doesn't stop people from resisting change... Even when it's a change that benefits them.
You don't need registry cleaners/fixers/whatever (on Windows) because they tend to cause more problems than they ever fix. Defragmenting is pointless for 99.999999999999% of people, and if you're part of the 0.0000000001% who would benefit, there's an excellent chance you'd know it. Virus scanners are (currently) unnecessary for Mac OS X, and have less and less importance on Windows with most threats now moving to exploiting applications like Flash, Internet Explorer, etc. If you avoid dodgy websites, don't run your mouth off on the wrong forums and chat rooms, keep up with security patches, steer clear of file sharing programs as well as pirated movies/software/music, and know enough not to open any random attachment sent to you in an email, you've pretty well done everything there is to be done. The routine maintenance will be handled automatically. Just sit back, enjoy a beverage of your choice, and go about life.
Is there a Mac OS X utility that does all the tasks done by Disk Cleanup utility in Windows in order to keep the operating system running as fast as possible?
What is your personal maintenance routine? Do you just do each task individually or have an all-in-one solution?