Computers have to be kept in a specific environment to function efficiently. Conditions such as heat, cold, dust and excessive humidity all can damage and lessen the performance of a computer.
Valve has announced that the Steam Machine is getting delayed as various computer parts continue to be hard to come by.
It's inevitable that, at some point, you'll have to replace old computer parts and swap them out for new ones. This might be a result of a particular component breaking or because you want to upgrade ...