Surge protectors--how many $ make sense?

Sorry to hear about your loss. Living in San Francisco and Los Angeles I had to pay a lot for real power conditioning.

The absolute safest, and most affordable solution is this Furman with voltage regulation, series protection, and automatic over/under voltage shutoff.

This comes up so often I wrote a blog post with more detail here.

I also wrote specifically about hos a whole house unit and high quality surge protector work here and why you need both.

Basically a whole house unit has a much higher let through voltage than the best surge "strips."  Good for your range, not so much for your laptop or audio/video gear. The manufacturers recommend the use of both.

I forgot to mention that on new construction and work done on existing systems, a whole house surge protector is now required as I understand it. 

I forgot to mention that on new construction and work done on existing systems, a whole house surge protector is now required as I understand it. 

As of 2020 the NEC requires it, local codes will vary.  Among the things they protect is the house wiring itself, as well as anything else you can't or wouldn't normally put on a surge strip, like fire alarms, GFCI outlets, smart switches...

Yep, @erik_squires and there is a 2023 edition with further "clarification" on the subject but it depends, as you said, on the locality. This link purports to identify state by state adoption of the NEC and which version applies: https://www.mikeholt.com/necadoptionlist.php#:~:text=The%20NEC%20is%20adopted%20and%20enforced%20at%20the%20local%20level. 

I don't know (this is where @Jea48 comes in) whether, if the state is stuck on an older version of the Code, a county or city within it can demand that the newer Code edition be enforced within its jurisdiction.

+1, whole house surge protection. Given your current system, don’t compromise performance by installing Furman or similar type of surge protection devices. They will choke the life out of your audio system. And they can’t handle high current amp so what’s the point…..

https://www.vhaudio.com/environmental-potentials-ep-2050.pdf