If you live in more harsh condition in that you get alot of road film and other contaminants. I would not be afraid of chemical decon wash regualary when haveing a coating or coating lite. They are really good at stand up to chemicals and I do it at least once a month. The thing to be carefull to use is chemicals with a higher ph level above 11 and under 2. So decon wash with letting the chemicals do the work in the prewash stage. To loosen up so much as possible of the road and other contaminants. Then when you first touching the paint with the wash mitt you have a better cleaning ability than without the prewash. Last wash I did on my car most would say that the lower side panels and the back of the car was done and needed to get a new lsp. But with a dedicated prewash foam and foamcannon to get the loose dirt and some imbedded grime clean rinsed off with the PW. Then a tar degreaser to get the other kind of imbedded grime off and clean rinse from the PW again. The following 2bm wash was a breese to do and got what the eye can see it squeeqe clean. When I dry rinsed it the sheeting of water was back at full strength of the whole car. If I do this regualary IME the imbedded grime is less on the paint than only doing 2bm washes. I use gyeon wet coat and it's holding up well since early december in Swedish winter weather.