i keep all my receipts in my file cabinet. especially for my wife's cobalt because she has a warrenty, and every once in a while gets her oil changed at wallmart and not at the dealer. i have never changed the oil in her car. what a good mechanic i am eh haha.. it cost 36bucks to get it done at the dealer, and it cost 26 for me to buy the oil and filter.. im not putting the car up on jacks and climbing under it for 10 bucks lol. my escape can be put on the hoist at work so its not a big deal. the car is to low to the ground for our industrial ramp lift.