Speed up your Mac

A reader who has switched from a Windows PC to the Mac, has a general maintenance question. I have some specific suggestions. He writes:
I used to reformat my PC's hard drive yearly to clean out all the files that slowed it down. Then it would run like it was brand new. How often do I need to do that with the Mac? I want to clean it up, make it run faster, etc.
There are two schools of thought on this oft-asked question. They fall into these camps:
Never ever.
I'm not a Windows guy, so forgive me if I paint this incorrectly, but my understanding is that this kind of advice is thrown so casually about because attempting to locate and cleanly dispense with all the dribs and drabs of cruft that slow down a PC can be the work of an unpleasant lifetime. So, rather than propel yourself into such a time-sucking hell-hole, you start fresh.
But again, not a Windows guy so the reality may be far worse than I've posited.
Although I've heard of Mac users taking such a slash-and-burn approach, I honestly can't recall the last time I did such a thing. Instead, you might try these techniques:
1. Restart your Mac every so often.
Like battery-sponsored bunnies, a Mac running OS X can stay on its feet seemingly forever. Launch Terminal (found in /Applications/Utilities) and enter uptime. You'll learn how long your Mac has been running since the last reboot. If it's been trotting along for weeks, restarting it may afford it the opportunity to flush out some old junk that's slowing it down.
2. Keep the desktop clean.
If you have a lot of files on the desktop your Mac will slow down. Tidy up those files by placing them in folders and the Finder will be snappier.
3. Slim down the contents of your hard drive.
If your hard drive is nearly full, your Mac will run more slowly. Archive or trash old files you no longer need.
4. Add RAM.
More RAM can speed up some applications.
5. Restart your browser and clear its cache.
Browsers are notorious for slowing down after they've been running for a long time. If you find that your Web surfing has been reduced to dog-paddling, quit and restart your browser. If it's still slow, clear its cache. In Safari choose Safari -> Empty Cache. In Firefox choose Firefox -> Preferences -> Advanced -> Network and click the Clear Now button.
6. Check login items.
Background applications and processes can slow down your Mac. Open the Accounts system preference, select your account, and click the Login Items button to take a gander at what's slated to run at startup. Do you need everything it lists? If not, delete the unnecessary items.
7. Check Activity Monitor.
Launch Activity Monitor (found in /Applications/Utilities), choose My Processes from the pop-up menu at the top of the window, and click the %CPU heading. Look at the top several items. This tells you what's drawing most of your Mac's attention. Are there items there that you can do without?
8. Quit applications.
Per the last suggestion, it's very easy to run multiple applications on your Mac. But perhaps there are more running than you need. Look in the Dock. If you see scads of applications with little blue dots beneath their icons (indicating that they're active), quit those you aren't planning to use in the near future.
9. Speed up your wireless network.
There are times that your network is the bottleneck rather than your Mac. If you suspect this is the case, take a look at Macworld contributor Glenn Fleishman's Speed Up Your Wireless Network. It's the goods.
10. Buy a faster (or different) drive.
A faster hard drive can speed up your Mac as can a solid state drive (SSD). SSDs can have read and write times that are four to five times faster than a standard spinning hard drive.