Many of us do so at least once a year, many of us do it even more frequently. Drag racers try to squeeze that extra mile per hour out of their machines, we try to squeeze those extra Frames Per Second out of ours. Upgrading or building a computer system is not as hard as it may appear.
Many people shy away from building their own system out of fear.
They end up buying a pre-built system such as Dell, Gateway, or Compaq. While these are not bad systems and usually very stable, they are not usually the fastest or best performing system you could have bought with your hard earned cash. I can't remember the last pre-built system I purchased. To truly get a solid gaming system, it is pretty much a given you will have to build your own. With a little research on the web, and some questions on a forum like the one here at SimHQ, you can get a wealth of information, and opinions, on what to look for and what is the accepted best performing piece of hardware for a given application.