You can also add additional devices, such as CD drives and burners and additional hard drives, but these are a bit more complicated than the memory upgrade described above. If you can't perform the upgrade yourself and need to hire a professional, weigh the costs carefully. Once you factor in the cost of the parts and labor, you may be better off buying a whole new system.

When to upgrade. The rule of thumb should be this: Upgrade when the cost of not upgrading exceeds the cost of upgrading. New hardware should help you work faster and more efficiently. Or maybe you need to upgrade your hardware to run new software applications that will improve productivity. If that's the case, upgrading is your best bet. Similar situations include a broken PC, one that crashes regularly, or otherwise keeps you from doing the work you need to do. Clearly, in each of these cases, it will cost you more to put off the upgrade than to go ahead with it.