I usually keep my cars for about 7 years. To maintain the paint like new, I never put them through an automatic car wash of any kind. They've always been hand washed. You may think that's a bit much, but most people are amazed at how good my cars looked at 7 years and I've always gotten a premium at resale.
Also, I've always waxed my cars every 6 to 12 months or so. Do people still wax their cars? I read somewhere that the new paints are harder than the old paints and don't need to be waxed. Any opinions on this? I live in the snow belt and like everyone else in this area, I get lots of snow and salt on my car.