resurfacing disc

how important it is to resurface the brake disc’s on a 13 year old car. i have done it before on some old practice rotors in class and they turned out ok. i just dont want to mess mine up and have to buy new ones. they dont make any noise or vibrate and they stop fine. just want to know if i should get it done while the car is not running or i wont have any other time to do it.
ps - i dont know shi* about brakes or suspension

Just pick up a new set, they’re $20/each at advance auto.

why dont you just get it done at a kragen or something they know what they are doing and do it for about 10 bucks.