Keep the Water Out.
Sounds simple...but unfortunately many "carpenters" are more worried about speed than proper techniques. Is this case, flashings were not installed over the window trims and allowed water to get into the framing. First it rotted the trim, and eventually damaged the hardwood floors in this very nice sunroom. We are happy to cry out "Bring on the Rains" after replacing almost all the trim with rot proof PVC and of course, installing the proper flashings and sealants.