I recently painted a two story house that was absolutely filthy. The owner wanted all the rooms painted, ceiling and trim included with windows and doors. While not a full time painter, I love to paint and am good at it.
The trim had already been painted as someone had covered beautiful mahogany or walnut trim with paint. To make the job quicker I used a short nap 3 inch roller to apply the paint and then brushed out with a cutting brush.
The result was an amazingly good paint job with time cut down. This worked quite well on the doors and windows.