Your credit score has massive power over your life. The three-digit number can open a lot of doors, including helping you rent an apartment and giving you access to a higher tier of rewards credit cards.

But if your credit score is sub-par — Experian classifies 300-579 as a "poor" score and 580-669 as "fair" — it can also hold you back. Having worse credit will get you higher interest rates on loans, which costs you extra money.