Have never washed the outside of a car in 25+ years of owning cars. Mother Nature rains eventually and does it for me. Cars are a time and money suck...why give them more than I already do, considering that each day that goes by, they're worth less than they were the day before and no amount of washing or doting will change that? Never made sense to me, but I can understand the allure for some (cars are a personal status symbol/hobby for many...just not me).
I do clean the inside of the cars we own for sanitary reasons of course. Maybe once every 2 months with a shop vac for the rugs and seats and some windex for the glass. Gives me an excuse to be in the garage for an hour with a handy IPA (or two).