I wash my car every other weekend, and it remains a beaut. I use that TurtleWax Extreme Car Wash & Wax concentrate (something like $4/gal. @ Sam's Club). I've also learned with washing my car later in the day (when the sun has almost set), drying it thoroughly with "The Absorber" (picking up any stray water drips after first-pass of drying), parking it immediately in the garage after a wash, and other-wise leaving it in the garage (esp. after 8PM, or so, when mist starts falling/accumulating) throughout the day when it's not used, I've been able to keep it in good condition between washes---almost so that the 2-week wash isn't even necessary! 😉 🙂
<< coz the layer of dirt is actually acting as a protective shield against dirt, dust, and small rocks that may scratch your car... >>
That's a new one... 😀