A recent question and answer here makes me wonder what is the best strategy for keeping a sunny outdoor wood surface painted. I assume that paints decay from the outside in, if the surface will hold paint reasonably. On sunny locations, the surface will oxidize and eventually the whole paint layer cracks.

It makes me wonder what the least expensive strategy is. Let the whole mess crack and peel, and then scrape and sand it starting over? On the other hand, it seems like it might be easier to scuff the surface and put on another layer of paint before it starts to crack. Any opinions among experienced exterior painters?

I just scraped and primed the Southwest gable trim wood on my house. the sun made it a mess. Fortunately, it is high enough that no one can tell if It is smooth or not ;-)