My pro/amateur hobby is finding great used frames, building the bikes out with Campy (Road) or Shimano/Sram (MTB) equipment with a basic goal of trying to make the best bike that I have ever ridden, for each of those two types. If I succeed, I keep it, and sell the one it beat out. I am no longer into MTBs so much, so I have one of those, but four road bikes.
I ride every single day, rain, shine, snow–whatever, unless the wind is hurricane level or the rain is of typhoon proportions–I’ve missed 10 days so far this year, riding an average of 30 miles per day (more on the truck-free weekends than on weekdays). I have one “tourer” which I use for the longer rides (anything over 50 miles), which is set up with puncture resistant tires, a couple of strap-on carrying cases, and so forth. I have another for fast rides in the local area–when the weather is great, and I’m feeling great. And, a third for all weather easy riding–when I’m not so up to par, when the weather is foul, or when I’m riding with others that might be a bit slower–that would by my normal threesome–but, I built one more that was great (a true sprinter), and I’m not willing to get rid of the others, though if I got an offer, I would probably sell the easy rider–I occasionally put it on the boards.
In the other threads, I didn’t get how the number of bikes has much to do with sustainability, nor do I here–for what it’s worth, all my bikes are built out of USED parts, unless a client asks for new (I build bikes for others on request). And, a kind of restriction in my best bike build is that I don’t spend more than $1500 total, all in, for each bike.
I currently have a Storck CD 1.0, an Opera Leonardo FP (the original Pinarello Dogma), a Ridley Excalibur and a Ridley Fenix/Liz–all Campy Record or Chorus equipped (except all with Ultegra calipers, which I prefer over Campy), all compact cranksets except for a triple on the “tourer” (the Opera), all with Eurus of Fulcrum Racing Zero wheelsets–plus a couple of extras to keep them all running.