What is a 3-way switch used for & why would you need to install one?

A 3-way light switch can add convenience to large rooms, staircases, or any space where you may want to control the light ...
The New York Times

You Can Probably Install a Smart Light Switch on Your Own. Just Don’t Cut the Red Wire.

We independently review everything we recommend. When you buy through our links, we may earn a commission. Learn more› By Liam McCabe I made no fewer than five mistakes trying to install a smart ...