I live in Southern California. I use Meguiar's Ultimate Quik Detailer on my Smoky Granite Mica ISF about once a week (or as needed). It is an excellent, excellent product, and I highly recommend it. It was actually recommended by my service advisor at my Lexus dealer, who is really into restoring old muscle cars as a hobby.
It takes me about 15-20 minutes to detail the entire car with the product. Like it says on the bottle, it is called "the missing link between washing and waxing." It does a very good job, and once I am done, the car looks like new, almost like it just drove out of the showroom. I always get compliments on how clean I keep my car.
I keep a bottle of it, with a microfiber towel (again, I prefer Meguiar's towels), in my trunk - I always use Quik Detailer the second I notice bird droppings, garden sprinkler water, etc... on the finish. With the warm southern California climate, stuff like that can get baked on, and as a result, damage the finish.
I take the car to the car wash (always hand wash - it's my personal preference) about once every two weeks or so (sometimes once a week, depending on how dirty the car is). I have the guys at the car wash wax it about once a month or so.
