What determines whether or not you should scrape or strip the paint off of exterior woodwork? I realize that stripping would look nicer, but it is a lot more work if the paint isn't that bad. I have some areas that aren't peeling, but are just sort of "crackled" from years of neglect. Is it good enough to just scrape the loose material off, prime and paint? Above all else, I want to do a good, lasting, attractive job.