<prompt> Human: My friends say it is smart to open a credit card, so they can eventually buy a house some day. Should I start now?  <response>: Yes, but NEVER let it go more than a month with any balance at all. Credit cards should be a way to delay payment and get some purchasing protection, not as a way to borrow money you dont have.They come in handy in situations where a check or debit card is useless.Also, your ability to get a low-interest loan for a car or house someday will be helped by having the longest credit history you can have. 