To get back to your original question - once a week (as long as its above freezing) mine gets washed. I use Meguiars Gold Car Shampoo. I've tried a bunch of car wash products and that one seems to have the best suds. After washing and drying with a blower/100%cotton towels I use a detail spray. All detail sprays have wax in them. Once a month it gets polished and once or twice a year its gets clay. As long as you keep the car waxed/polished I don't think you have to worry about washing it too much. I know my neighbors think I'm crazy but I also have a 5-6 year old car that looks better than when I drove it off the dealer's lot new.
And no I will never use car wash.

I'll do the edit down here. My good friend Mike from Orange has let me know that not all detail sprays have wax/polish in them. I thought I read here they all had some in them. So my bad. None the less it's better to use than not to! Thanks Mike!