While we’re definitely advocates for making a lighting plan for every room in your home, the bathroom is the one space where we’d say it’s an essential. If you’re renovating, this is something you should do right at the very start, around about the time that you decide on the room’s layout. You also definitely don’t need a designer or architect to do this for you.
It’s easiest to design your lighting plan on paper. We’d suggest taking your bathroom’s floorplan and laying a piece of tracing paper on top (that way, you can easily throw it out and start again if you decide to make a change without drawing or printing out another floorplan). Mark out the edges of the room on the tracing paper, then simply add in where you’d like each form of light – wall lights, pendants, spotlights, recessed LEDs, etc. Use a different symbol for each type (stars for wall lights, circles for spots…) and make sure you include a key. You should also mark the position of any electrical outlets on this plan too. Finally, add the position of the light switches if they’re moving (this is also where you can indicate how many gangs you want on each switch).
Be as specific as you can on your lighting plan. For instance, indicate how high wall lights should be positioned (about eye height tends to be the most comfortable), and how far apart (it’s a good idea to know at least roughly how big your mirror will be at this point). That way, if you’re not on site when they’re installed, you won’t come home to any costly surprises.
All that done, pass your plan onto your electrician.