I'm in Florida and keep my Insight garaged. As with every new car I've owned, at first I am a bit OCD and hand wash often (sometimes twice a week) and wax every couple of months. As soon as the first significant scratch, dent or other blemish that I can't hide destroys my once perfect car, then I hit the auto car wash. A friend of mine owns one right near my home and gives me a booklet of free washes for my birthday, etc.
I've always kept my cars in really good condition - inside and out. I never allowed my kids to eat in my car and made them empty their pockets before getting in (mostly to avoid puncture holes in the leather). I use a plastic floor mat over the carpet one and vacuum them all after every wash.
This is the first car where my wife and I regularly switch depending on who is driving further each day. She usually drives it 3x a week and I take it 2x. I'm striving to keep the Insight like new and keep that new car smell for as long as possible, but it is a challenge with her driving that much. She was about to take it to pick up 7 pizzas for a kid's birthday party this weekend when I had to rush out and confiscate the keys.
Finally, I keep a micro fiber cloth in the car to wipe down the dash and video screen - can't stand dust and fingerprints. My wife thinks I'm a bit over the top, and she is right, but it is such a nice feeling getting into a perfectly clean car - and friends always comment how amazing my 2006 Accord looks.