Very straightforward to wire in to the existing switches except one I did not have a neutral so I’m going to have to come up with something different for that location. I have nine installed now and three more just ordered. Once they are installed it just takes a few minutes to get them connected to my network and Alexa. I have a routine that comes on at sunset and turns on the lights on my back patio, upper dock, Front porch, screen room and 4 foot tall light houses that are on my deck. When I go boating at night the lights on the upper dock make it easy to find my dock and as I get close I turn on the lower lights which lights up my entire dock. Really a big fan. I have gradually replaced my Control4 system lighting with these. No more paying $150 for a switch and then having to deal with a prima donna home automation company (min $150 for anything, normally much more) to do a switch set up and having to call them back every time I need any minor change. I sold my 3 old Control switches for enough to cover almost my entire cost of Amazon smart switches. I also don’t miss the $150 a year subscription Control4 required for me to be able to control my system remotely we’re not connected to my home network. It is automatic with Alexa smart switches.
For installation I took the existing switch out and checked the black wires on both sides of the switch with the switch turned off. The one that does not have power is the red load wire and I put the red sticker on that one. Then it is very straightforward to wire the ‘red’, white, black and green to the corresponding wires coming out of the switch. I did have one box that had so much stuff already in it I could not fit the smart switch in. I bought a expander ring which is about a half inch extension to the outside of the box. I don’t love the way it looks but it certainly provides enough extra room for installation in a crowded box.