It seems to me that the best way to keep your tires looking good is to clean them off and re-dress them every wash.
I've used Eagle One Tire Cleaner, and their A2Z Wheel & Tire cleaner, but am more partial to Mother's Tire and Rubber cleaner. I use less of it and can tell if I'm using enough of it because it suds up slightly. A2Z strips off 100% of the old dressing, which you actually don't want to do because it could look blotchy when you're done.
Be sure to scrub them with a medium or fine brush that'll get into the cracks. Not scrubbing has been pretty useless in my experience.
When you're done washing and drying the rest of the car pat dry the tires and wheels before dressing, or you'll get water streaks. I'v just recently discovered cheap bulk shop towels (NON terry) work pretty well because they don't lint much, and when they get dirty you just toss them.
Some dressings are shinier than others, so read the description and do some experimenting. Some dressings can be buffed down to a lower shine or applied more thinly for less gloss. To each his own though. Sometimes different coloured cars look better one way or the other. Personally I find dark cars look better with shiny tires, but lighter ones look better with a satin or almost matte look. Even when I use tire foams which claim to clean the tires, I scrub them and use tire cleaner beforehand. I just don't see how anything can be cleaned by spraying something on and just leaving it.