In reference to which painted will last the longest.
You're on the right track as far as you should be using a high content latex acrylic paint obviously the more you pay the more fade resistant there will be overtime sometimes you can confuse fade with getting dirty or dusty which will make it lose its shine and then make it look like it has faded. The first thing I would do is wet to wall and check it again to the original color if it is the original color when it is wet then you might have a build up of some kind of dirty glaze. As a rule latex paint don't generally dis-color for years. Now mind you I don't stand and watch to see if some of our jobs have faded over the years but I have never had a complaint yet. One note though I always used top topline paints and mostly Benjamin Moore.
Comment by: Vic from www.diyblog.ca
and Toronto painters