Having a card even with a zero balance is still an open line of credit, and counts in how much credit you have outstanding. If you have a bunch of cards, closing the accounts is the better thing to do if you are planning on buying a house or car in the future. Keep 2 or 3 cards at the most. It will show you have good credit history. Having alot of "open credit" will count against you even if you don't have a balance. Cards that you close will have the message "Account closed at the request of customer" listed on your credit report. This is not a bad thing.

Every credit card offer you receive in the mail is reported on your credit report but does not affect your credit score. Call your bank and credit card companies and ask to be put on the "do not distribute list". You can also ask them to stop constantly raising your limit without your consent. Credit card companies love to extend more and more credit to their best customers, even if you don't need it. I had the limit actually lowered about 5 years ago on my credit card just because I didn't need 20K on 3 different cards. That is 60K in credit, which is excessive and could lower your chances of the best interest rate on a house or car.

just my 0.02