I agree 100% with Mike & Bobby, and I'd add that from my experience, a little extra TLC in the interior goes further to make your customer happy than those extra hours you spent "jeweling" his 1997 Chevy. If you can put yourself in their shoes, they don't "see" swirls and don't care if wax the door jams. They will notice the interior doesn't smell like beer farts and burnt motor oil.