I have 2 phone numbers - one from when we lived in another state and my work phone which is a local number. When I get unknown out-of-state area code calls on my personal phone, I do not answer. Anyone I know from when I lived there should be listed in my contacts. I answer local calls to my personal phone. This is the only time having the out of area number is valuable. Otherwise, it’s a nuisance and causes confusion. 
Similarly, if I get local area code calls to my work phone I do not anwer. All of my work contacts are saved, and anyone else work-wise can leave a message.
I don’t bother blocking. Each call only comes once. Also, I attempted calling a number back once and it was a real person’s number and he person that answered “swore” that they did not just call me.