NEVER allow some place to run a credit check on you unless AB-SO-LUTE-LY needed. Make them TELL you WHY they want to run one and why they can't get along without it. If they don't have a good explanation, tell them no. (I have gotten it in writing as to why they ran a check a couple of times when I wasn't totally convinced as to the need)
Credit Lenders etc get this look

on their faces when they see how many times in a given period of time (varies or used to) that someone ran your credit... It CAN result in a denial on a perfectly sound credit record. You can have a million in the bank, and have 20 runs on your rating and be denied!
Just a FYI for you younger people. ;-)p