A set of diamond drills will cost £50 quid and this cost should always be passed to the customer as a consumable. Kits are designed for use on very hard porcelain but will actually cut hundreds of holes in ceramics.
Ceramics are so soft they do nothing to the drills.
As part of every bathroom install you will have to drill some holes as part of the installation of any bathroom to fit the tiles. IE radiators, waste pipe.
Fixtures are actually part of the tiling job so there is nothing you can do about that. But FITTINGS are a different matter.
In our kit the drills for FITTINGS come as part of the kit and so you could always leave the rest of the kit with the customer to use for themselves (especially if you add the cost of the drill kit to their invoice as a consumable)
A BFKMX Kit is supplied with drills for the fixures (the drills behind) like radiator pipes, waste pipes, shower heads.
But also supplied with drills for the fittings (the drills in front) like mirrors, loo roll, shower screens,
At the end of the day its between you and the customer to work out where the job starts and stops. Knowing that customers would like a loo roll attached etc means you can now mention it right at the start of every quote.
You can offer to leave the drills with them to finish themselves at a cheaper cost, or add more time to do all the snagging and fixing. Hell if they pay enough money you could hang the towels, run the water, light the candles and sing "oh happy day.." while they use take their first bath!
My mate Andy is charging £5k per bathroom for a complete job start to finish and that includes snagging, cleaning, priming the radiators, plumbing, lighting, waste etc etc