Here’s a an X10 tip, which may be one of the last that I’ll have since I’m switching protocols:

If you’re having problems with an X10 wallswitch remote not working properly take a moment to check the orientation. The antenna works best when the device is mounted vertically, such as on a wall. It does not appear to work well when laying flat on a surface such as a table. It’s a bit of a “no brainer” but easy to overlook if the adhesive gives out and you get tired of sticking it back on the wall…