Re: Is caulking necessary?
True, grout lines can fail and allow moisture behind the tile, however it is a falacy that it will find it's way to the bottom edge and seep out on its own. What it will do is loosen the grip of the mastic holding the tile to the wall, as well as mold/mildew behind the tile. If you leave the tub/tile joint uncaulked, it too will allow moisture behind the tile and cause mold/mildew and eventual tile failure. Caulking is more than aesthetic, use it and make sure that the joint stays secure. If you notice the caulking starting to crack or fail, remove it and recaulk.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!