I currently have motion sensor light switches (non-X10) in my bathrooms. They look similar to these:
I use a switch like that one in the garage. I use another [non-X10] motion sensor switch type... in the
laundry room. It is just the wife and me... so I don't concern myself with the auto OFF function so much. What I like is the auto ON. The garage and laundry are areas where my wife seems to have her hands full carrying bags or baskets. It feels good knowing that (thanks to my efforts) she doesn't have to carry those heavy loads....
in the dark.
I think those same switches in the bathroom... would be more practical for the energy saving of the auto OFF.
We had those in the restrooms at work.. and they did save electric.
The switches work great!
MUCH faster than any X10 motion sensor setup I've ever seen. No rules that everything needs to be X10... although I can see where having them X10 would have some advantage's. I haven't ever seen any like them with automation abilities.
I know some people like to have the bathroom lights come on dimmed at night.... so the bright lights don't hurt the eyes. I've left the bathroom lights completely manual (no worries of them being turned off). Then I put a fancy [5 watt] nightlight(s) in the bathrooms... burning 24/7... in one bathroom. So I never NEED to switch on a light... unless I am shaving (I still use a blade). And I never need put up with too bright a light ether. Great WAF.