Q: At either end of my staircase I have a light switch that turns the staircase light on and off. The problem is that the switches don’t work correctly anymore ...

A light switch is the simplest of electrical devices. Flip the switch, electricity flows. Flip it again, electricity stops. Lights on, lights off. That’s great for a small room with one entrance.

There are as many varieties of smart light switches (and dimmers) as there are light bulbs, and while the prospect of upgrading your old dumb switch might seem daunting, they’re usually pretty simple ...