We all have this misconception about experience, that somehow time is a defining factor in determining one's expertise. However, the truth is that it's not how many years you spend in any endeavor but how you spend those years which determines your progress. Let's think about this for a minute.
The average practitioner trains 2-3 nights per week for an hour or so each night. That amounts to roughly 150 hours of training each year. But what about someone who trains as if it's a full-time job? Of course, this situation is rare now but there was a time when 40 hours per week training was considered the norm. You were committed to the art, and possibly even lived in the dojo. At 40 hours/week, you'd accumulate 160 hours of training in a single month. So then, in the course of a year you had nearly 12 times the amount of training as someone who only trains a few nights each week. Your experience level would far outweigh the number of years you've been training, and you would be greatly underrated. So how can we accurately gauge what someone truly knows?