Motherboards typically limit the number of internal solid state drives you can install. Most come with anywhere between two and four M.2 slots, though you can find options with support for more than that. But unless you have a specialized board, you may run out of slots eventually. That doesnt bode well for anyone who has a small collection of M.2 SSDs lying around. With purported shortages, it not such a bad thing these days to have extras, except you cant use them if you dont have any open...