1. Own a voltage meter
Get one. Really. If I hadn’t had this I would have shocked/hurt myself. I’d made the assumption that every gang (set of switch/outlets) would always be on the same circuit. This is not always the case. While replacing two switches in the bathroom that had an outlet in the same gang box, my screwdriver slipped and caused sparks. It turns out the circuit for the lights and the outlet were different, and I’d been fishing in around in a box with live 120V wires in it. I stopped and got a voltage meter.
2. Replacing switches will take longer than you think
Every time I thought “20 mins, in and out” it would take an hour. You’d open it up and realize it was a three-way switch with only black wires.
3. If at first you don’t succeed, sleep on it and come back
Usually when something didn’t work it was some dumb mistake I’d made that became completely clear the next morning. I’d spent 3 hours one day trying to add a “common” wire to my thermostat. I went to sleep. When I went back to it the next day I immediately saw that I’d flipped the white and black wires at the furnace. I’d been spending all my time upstairs at the thermostat.
4. Have an amazing partner
I turned off the lights, knocked out the WiFi, or had wires hanging out of the wall many, many times. My girlfriend put up with it all. I would’ve abandoned this a long time ago if she wasn’t so great. Additionally, when you install a new system, no matter how good, it WILL break for your girlfriend/wife/husband, and you’ll feel like a bad person for fucking up the WiFi.
5. Builders cut corners
I have five thermostats. Four of them had no common wire...and one of them was run with lamp wire. With that last one it was clear the builder and run out of wire, said fuck it, and picked up the closest wire he could find to make it work. Nothing will be exactly like the diagram, and when it is, it’ll feel like magic. I learned a lot along the way.
6. Measure twice, cut once (when buying equipment)
I did a bad job planning out my setup. Because of this, I bought a lot of redundant parts (I have a 24 port switch with no POE if anyone wants it). It’s best to actually spend the time planning out what you want to install before buying the parts.
7. Plan for more capacity than you’ll need
From compute, to ethernet ports, to power. Always plan for more capacity than needed. I’ve consistently gone over my own estimates. It also gives you space to experiment. Your first layout is almost certainly not correct. Excess capacity (more ports, power, or compute) gives you headroom to make adjustments.