For those of you who make your living (or part of it) building computers: what is your procedure for testing the system once its built, before turning it over to the customer? What software do you use? How long do you spend testing? How often does your testing find an issue and prevent potential later problems? What are the thresholds you consider acceptable for various things (max temps, max voltage ripple, etc.)? I've known a number of builders who slap a system together, leave it on overnight, and if it's still running in the morning, call it good. If you were the customer, what kind of testing would you want to know your computer went through before you bought it?