If you have supported a PC for a number of years, you have probably seen enough to be able to build your own PC from components. The main reasons I chose to do this were
The main drawback to this approach is that you have to be prepared to spend an indefinite amount of time resolving problems. There probably won't be many, and if you're experienced, there may be none, but it doesn't take many issues to soak up days of your time. Be sure to search the Internet and websites of your vendors for compatibility issues if you hit any snags.
In my experience, considering the value of my time (at least when measured in lost outside consulting time), the total cost of ownership is far less when buying a checked-out system such as from Apple or Dell. On the other hand, I value the education I have obtained from building and trouble-shooting my own machines, and I will continue to make Linux PCs from scratch in the future. Besides, I'm naturally optimistic, and surely the problems won't be as difficult as they have been in the past .