Reading through the forums I find that many posters quantify their experience by the number of training years they accumulated.
I'm only a beginner in aikido, but I am a 4 dan in an ancient japanese board game called go (in japanese). So I might illustrate my question with my road to reaching some level of expertise in a different field.
I've been playing go for 22 years. In the first 4 years I spent about 30 hours a week on study and competitive play. Most of my progress occurred during that time (Go ranks are based purely on competitive results). I reached shodan after training about 2 years (3000 hours) and 3 dan 2 years later (3000 hours more).
But after those initial years I've spent less and less time on studying go (job, family etc.). The years after that initial period I only spent about 5 hours a week on playing and I hardly studied at all. With this lower intensity training it took me 12 more years (3000 hours more) to reach 4 dan. In the last 5 years (1000 hours more) I seem to have hit a plateau, or perhaps a slow degradation would be a more accurate description.
So now I have 22 years of experience, but that gives no indication of the hours and the intensity of my training during that period and even less of the expertise gained during that period. I know many people who have spent 30 years playing go without reaching shodan in go. But they have only spent 3 hours or so a week, accumulating only 5000 hours of low intensity training total.
I've heard about the 10,000 hours rule for mastering any worthwile skill and I think that training hours would be a more meaningful measure of experience. And then the expertise achieved depends a lot on the way those hours are spent. My observation is that the more you progress, the harder it becomes to train in a way that promotes learning instead of just going through the motions, so learning experiences become exceedingly rare.
I've read some discussions about comparing O Sensei's students who achieved great expertise in 5 or 10 year with others who accumulated decades of training without reaching the level of O Sensei's students.
So how many hours have you spent actually training? Do you still strive for some level of training intensity after so many years? Do you still learn from training?