I discount experience when it is not related to what the job requires. PE teachers have to know how to count to keep score. But 15 years experience doing that doesn't mean they are ready to teach Calculus. You need a base knowledge that requires experience directly related or classroom knowledge/training. All these people that are saying that they learn the most "in the first year" have that knowledge as their base; they aren't going form zero to teacher/counselor/accountant/engineer immediately.
Since people seem to like memes around here. This is what comes to mind.