Ha ha ha I'm what they call a small time personal grower so my milestones are pretty modest and mundane.
But filling a mason jar with herb I'd grown myself was satisfying as was getting complimented by a couple of folks on the quality of the smoke and the buzz.
My biggest milestone was when I finally was able to clone with an almost perfect success rate. When I first started growing I had a real difficult time with cloning, I really sucked bad at it. This was way before I found these internet sites and all I had was this small book and wow it was so frustrating to keep losing strains I had been growing from seed. Finally I figured it out (and how simple it actually was) and from then I was able to keep the strains I was working with, and that changed everything and was a real big step for me. Now looking back I think how stupid I was for not being able to accomplish so simple, but man at the time it was frustrating to keep losing strains.