I have three ringtones for my phone.
My family or very close friends and if I hear that I know to answer it, if at all possible. At the very least, I check to see who is calling.
The other is for my general contact list. So if that goes off, I check and see who it is first to decide if I want to answer it.
The third is the carrier’s default ringtone and when I hear that, I just ignore it and figure if it’s important, they’ll leave a message. And on rare occasion they do.
But under no circumstances will I answer it from an 800 number or some oddball area code.
Good system! :)