We have a few pictures here which demonstrate some key points of what not to do when painting windows.
Looking at the first of the two images, you can see that the previous painting job was done poorly. The window areas had not been prepped properly before painting – as all of the sash areas should have been burnt off first as part of that preparation process.
It shows that the work area was not checked properly during painting as well, as it was obviously painted with the window closed leaving the interior area of the structure unpainted and unprotected. That brown internal area at the bottom of the window is considered part of the structure and should have been painted as well.
Very importantly, it can be seen that the person just painted over the old paint. The surface areas had only been flaked and not taken back to the bare clean surface, which should have been completed with scraping or burning.
Aside from not looking very good, the paint job will not last very long and it would have peeled in due course, possibly leading to damage to those areas – and additional cost to repair.
It’s great to do jobs yourself, but there is a lot to be said for getting professional painters in!