Credit is a fickle bee otch...
It can be useful, but if you don't use it enough you get penalized for it more than if you misuse it.
One of my buddies has made some poor financial decisions, and has been working to fix it. He's in a strange spot because he's behind on payments, but not very far, so what do the big CC companies do? Offer him more CC's at horrible interest rates, or up his limit.
Credit can be very useful, or it can be the path to indentured servitude in modern society...