When first meeting another rider one of the first small-talk questions I ask is "How long have you been riding?" Sure this kind of helps gauge the experience the rider has, but then again... does it really? I think not. I think a better question would be to ask how many miles he/she has under his/her belt. As I meet more and more riders, a lot of them have 4-5 years of riding behind them; however, it usually turns out that they have only ridden 5,000-10,000 miles.
What's your miles-logged measuring stick?
I've talked to a lot of "real" riders, and they said they stop calling others newbs when they hit the 30,000 mile mark. I think 30,000 miles sounds about right.
In my 4+ years, I've ridden over 43,000 miles, and I've learned that I still have a lot to learn.
"The only true wisdom is in knowing you know nothing." ~ Socrates