I don’t know about you, but I seem to always be running out to the store to buy extra hard drive storage. I never seem to have enough! The fact is that whether you’re running Windows or Mac OS X, your system will slow down over time. It’s not unreasonable, considering how many applications, music, videos, and pictures we cram onto a single hard drive! Take some time to backup some old photos or videos to a separate hard drive.
Spend a few minutes removing the applications that you no longer use. AppZapper is a great application for removing programs from your Mac. As a general rule, try to keep at least 15 percent of your hard drive free at all times. When the computer drops below that, your performance will be affected because of the Mac OS X constant file indexing. Drop below 5 percent free space and your disk integrity may become compromised.
If you haven't upgraded to Mac OS X Snow Leopard, be sure to do that, as it recovers 6GB of hard drive space when it is installed.