This has been discussed in a couple of different threads recently. But since distance is common word it makes it hard to search for.

You're going to get lots of different answers. I'm training to do Paris-Brest-Brest next August, a 1200 K ride, completed over 4 consective days. My rides range in length from my 4.1 miles commute (that's round trip!) to 200 miles. I usually ride 6 days a week, sometimes 7, because I commute.

People who mainly mountain bike will have lower mileage. Folks who are "normal", not mental, won't have rides longer than a metric or imperial century, maybe they will do a double metric.

Some people are weekend warriors, some commute 20 or 30 miles to work everyday.

We are all different.

V.