I am working on a game and want to strengthen its requirement checking to ensure that it can run successfully. Therefore, I am looking for information on what is useful to check before starting the game. As a simple example, Why check for a specific amount of memory? Should I as a game developer ensure a minimum amount of memory? I feel this information is usually skipped in many books and resources but is critical to be able to deliver a game that will run on many machines.

I would appreciate if you answered with what you check in the system, why you check it and if you have a good resource about it, please include.

Just to be a bit more specific, I'm developing in Windows.