I always go with 3 (except with reds---they always need a lot of coats to cover the streak look).
I hope it doesn't come to that.
Her room has always been a little colder than some of the others, and after I took the trim off I noticed a definite draft. That part of her room hangs over (extends past the basement) and we think there might be little insulation in there. In that corner of the room, there are strange streaks that look like we totally forgot to paint in that area.