One of the things I've liked about using Linux on the iBook is that whatever maintenance goes on goes on strictly in the background. Seriously, whatever it's doing to ensure safe and reliable operations, I don't want to be bothered with it. Just do your thing, Mr. (or in the case of the icebook) Ms. Computer, and I'll happily continue surfing/writing/audiophiling with nary a worry or distraction.
Things are different in OS X. At least we're told. Ever since I started using it, I've been informed by people more knowledgable than me that you had to keep your Mac "clean." One of the earliest utilities for this was Cocktail, which ran maintenance scripts to clear out old log files. Now, these scripts were set to run periodically in the background, but because they didn't reliably run on schedule some users felt it necessary to run these manually with apps like Cocktail. 'Cause having log files build up to literally a few megabytes of disk space was an intolerable situation.
As OS X passed from Jaguar to Panther to Tiger to Leopard/Snow Leopard, many other "maintenance" apps appeared on scene, probably most prominatly Onyx. This utility does all the maintenance you could ever want. It runs maintenance scripts, it clears caches, and repairs permissions, etc. And all of it is a complete waste of your time.
That's right. Running maintenance scripts are a waste of your time. Clearing caches are a waste of your time. Repairing permissions, same thing. As a matter of routine "maintenance," these actions not only waste your time in executing them, but in the case of clearing caches, will actually make your computer operate slower. The only reason you should ever clear caches or repair permissions is if something's going wrong, i.e. if you're troubleshooting. And maintenance is not troubleshooting. In fact, I'd even say that repairing permissions and clearing caches are almost always a waste of time in troubleshooting, too. The only surefire troubleshooting method I've found is Google. It's uncanny how no matter what problem I'm encountering, some other user has had the same problem and has written about it in an easy-to-locate search result.
In OS X, there is only one form of routine maintenance you need to be aware of: keep ten percent of your hard drive space free. If your hard drive fills up too much and lacks the space to create a proper-sized swap file, it will lead to major slowdowns. If all your applications start to feel sluggish over time, that's probably the cause.
So free yourselves from your fellow Machead's tyranny of maintenance. Life's too short. In over four years of running the same Tiger install, I haven't done any of that stuff since the early days when I didn't know any better, and it still runs as fast and smooth as the day I got it.