A: BOTH: Read Below.
If you're getting ready to prep and paint a ceiling and want to protect the flooring you should take a few simple steps. 1st: use painters plastic on all furniture, the tops of cabinets and carpet. 2nd: Use tarps on any wood or tile surfaces. Generally I recommend using tarps on surfaces that are slippery (in either case be careful). I personally buy the plastic backed tarps or thick woven tarps which are a little more expensive but block any spillage.
What tends to happen is paint splatter from the roller falls down and as you walk around some of it will stick on your shoes. Make sure you prep the area so you are always walking only in those areas where you have something on the ground (or outside). Then take your shoes off before moving to those areas that are not protected.
I see a lot of ceilings that have roller marks in them, un-matched texture, roller lines (because they were rolling too long or pressing) and then we get called in to fix the mess. We appreciate it.
Specifically with texture repair, I am consistently asked to fix areas that were butchered by someone that didn't know the correct way to do it and didn't have the experience.
Painting a ceiling correctly is not as easy as you may thing, and there are more steps than you think. If you are going to tackle it though. Take the time to prep the area correctly by covering everything,...everything.
Call Nick at Complete Custom Painting
Twin Cities, MN Painter