Also, I would check reviews and previous sales experience. 

It's a fairly unregulated space (charging grandma $750 to puts around for 3 hours, after moving the old box from the horizontal sensor, which was the only problem with the garage door to begin with), so some combination of carefully reading reviews (you have to actually read them to make sure it's not 200 fake reviews), and maybe not giving them the full contract all at once, is in order. 

You can also search Google and read reviews.

You can also search Google and read reviews.

Yelp is a good source because it lets you read reviews of actual customers.

Guests seemed fine with this (or would say something privately, thank goodness- not in reviews).

You can also search Google and read reviews.

I also hire one of the big national 20 CPA firms to review returns every 2-3 years. 

Quote from @Roger Flot: I was reviewing some renovated listings in my area and one indicated that even though the house was originally built in 1920, because of all the renovations bringing the house to current code, that you could get 2024 rates on insurance. 

If you're anything like me, customer service is the main draw for me when I am choosing any service provider.Look at websites, reviews and testimonials.