I've been having problems getting paint to stay on my window frames and sills (exterior). With several of mine, which I've painted over the last 1-3 years, the paint (that's primer, undercoat and gloss) has just flaked off right down to the bare wood. I don't know how long I should expect exterior gloss to last, but there are one or two windows which I still haven't touched since moving in 10 years ago, and they look in better nick now than some I painted 2 years ago.
What am I likely to be doing wrong? I've always stripped the old paint back to bare wood (usually with a hot air gun), sanded it smooth, ensured everything is clean and perfectly dry before painting.
Thanks David