About twice/thrice a year, I remove all of the wheels and clean the wells as described above.

THEN I spray them down with a tire gloss (Black Magic) wait and wipe. Keeps them clean and shiny for quite a while.

I just did the Tahoe wells before this trip with Meguiars Hot Shine Gel and they look great even after 1000 miles. For 100K on it-it looks pretty danged nice!

P.S. Don't get the Black Magic on the tires-you won't like it. The Meguiars looks great though...