By the way, the trickiest part of the Lutron trick is what they call “phase adaptive” switches… The switches are able to detect the amount of power that the bulbs require and then they adjust the amount of current to match that. That’s way smarter than a typical dimmer switch. And it’s the reason they can run a switch without a neutral and still dim a CFL or an LED, although not all brands.
A typical switch sends the same amount of current regardless of the bulb type. It just adjusts the amount it sends based on the dim level requested.
The Lutron switches are also detecting how the bulb is handling the current and making adjustments on that basis. It’s really high-tech. And exclusive to them.
They are also able to determine polarity for the incoming lines, which is why it doesn’t matter which screw you attach the hot to, which is completely bizarre.
They can’t do this with all of their switch models, so you have to check each one. The ones that include a motion sensor for example, do need a neutral.
But Lutron does more engineering R&D on “simple light switches” than pretty much anybody else. And it shows in their results. (Phillips, Osram, and to certain extent Cree, do a great deal of engineering work on bulbs, but not that much on switches.)