The problem with sanding off lead base paint is it becomes airborn allowing anyone in the area to breathe it in. Children and elderly are especially sensitive to lead poisoning. The dust will settle on all the walls and some will stick to the ceiling. Even creep into your ductwork. Once in your ducts, it will blow out into the air when hvac runs. Test that finish before sanding! Strip it if it has lead. This has to be done especially if you have children. Otherwise, cover it back up with carpet.