Excessive amounts of water and wood don't mix.
Wood is a natural material that swells when it absorbs water and shrinks when it dries. Wipe up spills as soon as possible to keep your floor unmarked, smooth and level.
Grit is one of the biggest dangers to your floor.
Tracked in dirt is like sandpaper on a hardwood floor. Use a walk off mat or an entry rug at every outdoor entrance to catch the grit. Vacuum or shake out regularly.