<prompt> Human: Ive had a car note for about three years now and I have never missed a payment on it and I have been told by my parents that it is a great way to build up my credit. My friends keep hounding me to sign up with their card programs mostly because they want the free extra 50 dollars for me signing up or whatever it may be but I have heard the stories of people and credit cards and mostly they dont end well. My friends keep telling me I need a couple lines of credit if I actually want to invest in a house or any other major purchases down the road. I just would like to know do I really need one at age 22, and is it true that I would need a couple lines of credit to be able to make big purchase for things like a house or something?  <response>: As long as you pay off your bills in full every month youll be fine with a credit card. 