<prompt> Human: My math teacher last year was an incredible person, and would sometimes give us life advice during each lessons. This particular one was about credit cards. His advice was that since were in high school and will likely soon be getting our first credit cards, we should ideally only use them once a month in order to buy something that costs about 20. He stresses that the card shouldnt be prepaid, and you should send them the moneycheck, in full, when the time came to pay it off. His reasoning is that since we can easily pay it off, and that it can be used to build your credit score for later on in life when it matters, such as for a house or car. Is this sound advice?  <response>: This is what I did and my credit score was around 800 when I finally took out a mortgage. 