As I renovate my house, I’m looking to control a majority of the switches and lights with Home Assistant. However, I am wondering what would happen if I sold the house. Would I have to leave a running version of Home Assistant or replace the smart components?
Has anyone sold a home with Home Assistant still active? What do you change about your home prior to selling?
I would advise against it. Unless you are prepared to completely document your system and provide detailed instructions for non-technical users, you will likely be pestered with support calls after the sale. Also, it could potentially put prospective buyers off.
This could be a good business model. Renovate, setup home assistant, get buyer to sign expensive support contract 
It depends on the switches/devices though. If lights will always work at the switch regardless of whether home assistant is running, then you could leave them as they are and just remove home assistant.
If/when we ever come to sell our place, I’ll be more concerned by putting people off. I’d make it clear to the agent that I’ll reinstall normal switches throughout, unless a buyer particularly wanted them.