If you are building your own computer, you will find that there are hundreds of different cases to choose from. No matter what your needs are, with so many available, you will be able to find the right one. But what factors should guide your final decision?

First, the most basic is the “form factor” of the case. Everything from a full-size ATX to a mic is available. This also refers to the size of the motherboard it can accommodate. Note that an ATX can accept any size motherboard, but smaller cases cannot support a motherboard designed for a full-size ATX.

Also, in this step you will consider the layout. Do you want a tower? Maybe a mini tower would be to your liking. There are cubes, desks, and a wide range of variations.

Second, most people buy their power supply with the case. The minimum I can recommend right now is 300 watts, and that’s only for the most basic PC. A gamer or 3D animator will want 450 watts or more.

If you are building an extreme machine, you may want to purchase its power supply separately, especially if you are looking for the 650-watt level. This will give you a greater variety of sizes and designs.

Third, your case will have fan mounts to circulate air. In general, the more the better. Look for a case with two brackets on the back and one on the bottom. With today’s hot-running CPUs and graphics cards, these mounts are one of the most important features to consider.

That is, unless you’ve decided to go for a water-cooled case. These can be purchased as pre-configured units, saving a lot of trouble later in the build process.

Fourth, all cases should have USB and Firewire ports up front, considering how many digital cameras and other similar devices we seem to have now. You can upgrade to a 3.5 “bay if needed, but they really should be part of the original case design.