4 sets of tires @ 20K miles each. That's almost a set a year for normal daily drivers. If you're getting oil changed regularly that's three a year. Tires = $900, oil changes = $300 and if nothing goes wrong you've spent ~$100/month. Obviously those numbers are a little lower for people who don't need good tires and do their own oil changes. Please do the math and don't lead this poor OP down the primrose path. Over the life of a daily driver car you will spend what I said or you are deferring maintenance to the sucker who buys it from you. Chris, bless your heart, I wouldn't touch your car because you've done nothing in 90K miles.