It won't be detrimental, but it certainly is easier to do it first. You won't risk drips and splatters on your walls and you won't have to cut in twice. It is an unpleasant job, but, if you really think the ceilings have to be painted, it is probably better to just bite the bullet and do it now.

Since we paint our ceilings the same color as the room and my tall son (almost 6'4) does this, I go ahead and paint the walls as high as I can and he gets to the higher stuff for me. You do not have to paint the ceilings first! If he does load up a roller or edger with too much paint and it drips, he takes care of it right away and it does not make a difference since it's the same paint color.

We're doing white on ceiling and walls so I guess it might not matter. But yeah, may as well just get it out of the way. Thanks for all of the advice everyone!

I recommend painting the ceiling first! Even if you are doing white for both I find it easier to always start with the ceiling! Good luck!

You will be happy later on if you paint the ceiling first. Get a roller with a long handle, too. Good luck!

You do the ceiling first because the roller sprays the paint on the walls sometimes. Easier to deal with paint spray on the wall that is going to be painted, than a wall that has already been painted. If you are physically unable to do the ceiling then hire someone. It won't break the bank.

I just got finished painting my bath ceiling and I'm glad I did it first because I didn't use tape and I didn't do a perfect job staying away from the walls that just got primed. Obviously it's not an issue when you paint your ceiling the same color as your walls, but I'm not doing that in my baths. I ended up painting my walk-in closet all the same color because I did a terrible job cutting into my walls. I may still tape my ceiling before painting my walls.