Yeah, I answer nearly zero calls from numbers that aren't in my contact list. If it's important they can leave a message. If it's a local number I'll google it, and maybe call back even if there's no message and it seems to be someone I want to talk to. Out of state? No way. Most people I know—even my tech-unsavvy parents—have resorted to a similar policy. Multiple spam calls a week—more than calls I actually want to take, certainly—will do that. I'll start treating a ringing phone as necessarily worth paying attention to when junk calls drop to one or two a year, like they were for a while after the Do Not Call registry first came around.

It might be a good filter to find people likely to answer collections calls though, I guess.

I wish there were a way to tell the dialer app to not ring if the number isn't in my contacts on android.

I do this ever since I started getting a bunch of spam calls, and it's amazing. The dialer does still "ring" in the sense that it takes over your phone and you need to swipe-to-decline or wait it out, but it won't vibrate/sound except for those in my contacts.

For my particular phone (Droid Turbo) it's here: Notification bar > swipe down again on notification bar > Do not disturb > Priority only > Until you turn this off; More settings > Priority only allows > Calls > From contacts only.

There's even an option down there (sibling to Calls, in the flow above) called "Repeat callers" which, when on, allows a not-in-contacts call to ring if they called twice within 15 minutes. None of my spam callers ever call twice in a row, so it's brilliant for making sure I see (repeat) calls from food delivery people, uber drivers, etc. (although I feel bad that I missed their initial call).

Of course YMMV depending on model and version.

https://www.howtogeek.com/260225/androids-confusing-do-not-d...