This is less of a milestone than it looks, because it's been several years since I rode my bicycle. Various aspects of health and aging have caused that to drop off the slowly dwindling list of things that I do. What just happened, though, was a formal acknowledgment of that: we put it up on a neighborhood list, and yesterday someone came and took it away, and my helmet too.
A bike was my regular transport vehicle in childhood, but I stopped riding in early adulthood. Not feasible as a method to commute to work, less time to do it recreationally, and living in small apartments I had no real place to keep a bike. It was much later on, probably when I was close to 40, that I bought the bicycle I had up until now. It was the first bicycle I had with touring handlebars since child-size ones; when I got my first adult-sized bike, as far as I could see those curled-under racing handlebars were the only ones being sold. I always hated them, but I couldn't get anything else.
That touring bike did me a lot of service, especially after I got a hatchback car which the bike would (barely) fit inside with the back seat down. Since I was never a distance rider, this meant I could take the bike to places I wanted to ride around in. There's a scale of travel at which a car is too large and clumsy (and it won't go off-road anyway), and walking is too slow and wearying, so a bike is perfect.
Having been transported by car it took me: from a park-and-ride lot a couple miles to the Portuguese festival, avoiding the extortionary parking fees there (I did this more than once); to old town Willow Glen, where B. and I rode around the narrow streets looking at the marvelous old houses; up to the Santa Cruz mountains, where I rode downhill on a half-trail half-road that I'd wanted to explore for 40 years; to the Napa Valley, where I rode around exploring the sites that Le Guin turned into the villages of the Kesh in Always Coming Home.
Those were all grand expeditions, but that phase is over, so it's best to hand the tools on.