"Building Credit" with credit cards is a moot point. There are many ways to build credit, with a credit card waaaay down on the list of ways to build it.
My point is canceling a long-held credit card is an excellent way to harm your credit if you're on the bubble between good/bad credit.
If your credit score is 800 then cancel away... if it's 701 you'd be unwise to cancel cards.
