I used to mine a bit, testing different USB miners and my own computer (CPU mining) and got bored with maintaining it all for just cents. Mining is for two kinds of people. One is hardware geeks, that treat it as a hobby and like maintaining it and tinkering, even if they're earning very little. The other one is professionals, able to rent a airplane hangar and fill it with machines worth hundreds of thousands USD. If you're none of them and want to earn, forget about mining and buy Bitcoin.