A couple of years ago I bought a folding bike -- Bridgestone "Transit Light", from circa 2006 -- for ease of carrying in trains to and from sites for "pottering" (as it's called in my part of the world: slow, short rides on the near flat).
It's heavier than I'd unthinkingly assumed, and no attractive opportunities for "pottering" have arisen. But I use it for local shopping, for which its side-stand is useful. (Also, it cost me just ¥16,500 [currently €97], tax included; I'd lose little sleep if it were stolen.) From the outset, I found it rather hard to handle (after decades on no wheels smaller than 622 mm), but I reassured myself that I wouldn't be riding it up and down hills, etc.
But then the stupid notion of riding it up and down hills somehow acquired a macabre fascination. I've now taken it up and down some of the better-known of the hillocks that surround Tokyo: Yabitsu, Kazahari, Matsuhime. But until yesterday I, very sensibly, hadn't used it for a "century".
Done.
This was an unambitious ride, mostly along the near-flat:
but at its far end going up the minor but spectacular Nippara valley (oft travelled by
joewein ):
Done it; no need to do it again.
Another bike in this thread is so much more comfortable....