I suppose wives who are fed up with their husbands for having a permanently malfunctioning aiming system will be thankful for the Lavatory Navigator, or LavNav for short.
The LavNav turns on when you approach in the dark, and turns off after you leave, shining with gentle yet sufficient light where you need it, when you need it. The Lav Nav makes the toilet a lot safer and easier to use at night without irritating your partner. Bathroom lights can be painfully bright in the middle of the night. So why switch them on?
No idea on how much the LavNav costs though.