I always answer unknown numbers.

I don’t get scam calls or marketing calls. I’ve had a marketing ban on this number and it has never been listed and it’s about 25 years old or so. Like maybe once or twice I put it somewhere and got calls offering gym memberships for a while but that was a single place and I told them I have a marketing ban on my number so they stopped. It genuinely works to a very reasonable degree here in Finland. It’s not perfect but nothing is.

So when an unknown caller calls me it’s usually a doctor or some such thing I actually do need to reply to.