[seharper]

@SPS-1 That trick doesn't work, you can't say "I only need to provision 17W to this Edison screw-base fixture because I for one plan to use LEDs". You could sell the house to a cold-dead-hands type, and they'll put incandescents there. And yeah, they're still for sale if you make a bit of an effort, my sweetie insisted on them in 2 rooms so I obliged.

You don't have to provision for the largest bulb made in that base (e.g. 150-200W for Edison E26). But you do have to provision for the largest bulb the fixture is rated for: so if it has 3 Edison E26 sockets and labeled "60W max" then you must provision 180W.

And that ... is part of why many fixtures use new socket types such as Gu24, which are specifically designed to reject incandescent bulbs.