3 times a year, plus after any Mexico trips. The wash is good, but the
the wax is more important. I have a very laminar wing so I probably get
an extra knot or two with a smooth buffed and waxed wing. Its also
important to keep the wheel wells clean. There are a lot of moving
parts in there (retractable) that get gummed up with dirt and cost a
lot of money.

-Robert, M20F