Unless you are a very good brush hand, it’s best to tape up every thing you don’t want painted, before you start. New paint, once cured, is very difficult to remove. This especially so when painting up to tiles, where it’s desirable for a small amount of paint to come onto the tiles, to aid in producing a waterproof seal. Make sure the masking tape is firmly applied and leave no gaps, as the wet paint will tend to flow into them. Use Blue or Green masking tape from the hardware and remove as soon as you have finished the last coat or within a day or so of finishing. Also tape around fittings and so on, so they can be unscrewed later. Our paints are great at gluing things together!!