I'm going to paint a ceiling (standard 'ceiling white') that hasn't been painted in roughly 10 years. It's not really all that dirty for being so old, so I'll probably just wipe it with STP or the like. Should be no problem with new paint adhering to the old. But here's the question... I want to be able to cover with the least number of coats possible. Would priming it first be likely to cut the total number of coats (including the primer coat) needed? TIA.
---Mick