Hey Beer Man - We have a recent college grad that was a D1 wrestler and goes 1 for 1 with the browns in my school. He has picked everything up very quickly and usually is able to use a new technique in live rolling immediately after learning it. He'll get his blue in about 6 months of training. He body awareness is ridiculous and if I have to beat that guy everytime we roll I'll never get my black belt. Having said that, everytime we roll the only reason I have a chance at surviving the roll much less tapping him is my 10 years of mat time in jiu jitsu. For me, that is the true testiment to BJJ. I'm 50 and he is 25. I'm an out of shape 170 and he is a male model at 170. I'm not athletic at all and he was given a free education because of his athletisism.
This. I am a 52 yr old hobbyist black belt and have a hard time against the competition purples and higher that train everyday. I have been live rolling/sparring/randori pretty much nonstop for the last 25+ years either in Judo or BJJ and just have alot of wear and tear on my body. Although compared to many guys my age I am doing pretty well.
I roll with anyone who asks and against the tough higher belts I just roll to survive and for fun. I still do well against the lower belts and the higher belts. Most of my rolling is just to keep it playful and I do turn it up on some of my rolls, but noway can I roll hard every roll and not be super sore the rest of the week.
Anyway my idea of what a black belt should be is kind of old school. I think Helio Gracie had some comment about Jiu Jitsu being created for the weak to beat the strong. It was meant to allow a smaller/older person to beat a larger untrained person. So for an older brown belt I think how he handles a bigger untrained (or with some training) person who walks in would be my judgement on his skill level. In fact this is why I started Gracie Jiu Jitsu 20 years ago back when I was 155 lbs. To be able to defend myself against someone much bigger and stronger.