Funny enough, a local friend has a house and garage that dwarfs my collection. He has something around 150-200 bikes (always in flux, but usually growing). Mix of road and MTB that date way back to the 50s or before with plenty between then and now.
Walking through the garage is a maze of bikes side by side on the floor and hung from the rafters. I have more than a sane person should but he has the literal museum. He does regular FB posts with the age and history of each model. Pretty cool and he has more than I few I really admire. But I’d go OCD crazy with the mess he has on his hands.
I think I am with the OP - there is some point for me where N+1 equals too many. I just don’t want to maintain and store one more bike, and I do feel a little guilty to have it sitting there. And when I have too much overlap, I always pick the nicer bike, so why have the overlap? I think I have found my happy number (which is a luxury) at 5.
1 Road bike
1 gravel bike
1 hardtail mtb
1 full suspension mtb
1 first gen Santa Cruz Stigmata - I have 32 Roubaix tubeless tires on this, so it gets used for bad weather road rides, light gravel, etc. Full utility bike.
On the potential chopping block
1 fat tire mtb - in central illinois I am on the edge of needing a snow bike. This winter will probably determine it’s fate. If we get lots of crappy weather, it may stay.
1 old old old Raleigh 29er (the original XXIX if anyone knows that bike). Set up with some wide slicks for riding with the wife, running errands. I could do this on any other bike. But this thing isn’t really worth any $, so holding for now)
I have three road bikes and ride all of them over 500 miles a year. 500 miles is not a ton, but basically I do 50% on my oltre XR1, 40% on my colnago C40, and 10% on my 1987 bianchi sport sx.
I ride my oltre when I want to go fast (races and sometimes I just want to hammer it). I ride my colnago on most z2 rides. I ride my '87 on errands, an evening stroll, and a couple of longer rides each year.
Another benefit of having multiple bikes in same discipline - when you can afford it - is the ability to invite friends on rides who do not have a bike. I organize a couple of social rides with friends each year and I always borrow at least 2-3 bikes to friends.
Honestly you are putting in 400-600 hours a year, i think that justifies having more than a few bikes. Having a full quiver has its disadvantages but as long as you have the space, financial ability and can do the basics of wrenching on them, why not add to the quiver. I think riding a diverse set of bikes adds to the enjoyment of the sport, avoids burnout and progressive repetitive motion injury. Disadvantages are many but the main is that there is always something that needs to be done, none of them are ridable 100% of the year and it gets expensive even if you do share wheelsets with a few. Its time consuming maintaining a big fleet, I average at least an hour a week wrenching, probably more.
I put in about the same amount of hours and have about 8 bikes (main roady (3T strada), crit bike (SC Roadster), FS MTB (Yeti SB115), hardtail/SS MTB (SC Highball) 2 CX rigs (because you gotta have a pit bike Lapiere Carbon CX;s) Fixy/track) (Masi cotello) Gravel (Willier Jena) CX SS (Lapiere glued to my trainer) whew i think that’s it, makes it sound a lot worse when you write it all out).
Objectively (concerning space, finances, girlfriend) nothing speaks against a new bike which makes the whole thing a bit absurd from a consumer point of view (the “why not?”-question).
I think this is a good point. A friend of mine asked: “What gives you more joy: The money lying around or this new bike?” But then I’m not sure how much joy a new bike really brings me, since a lot of needs are already satisfied. - Also I am still “young”, no kids yet, so I may still have a lot to learn.
Also a good point: It’s nice to be able to take turns if you want to, or if the journey makes it necessary. Every bike is a bit different and there is something about it.
I think one aspect is that I haven’t been cycling that much for that long (less than three years). This means that the hobby is not yet fully established and I wonder to what extent such a purchase is worthwhile over time. Under this aspect, less is usually more.
On the other hand, my first road bike has served me well in this regard (Decathlon road bike for 600€ with around 5000km outside, now full time on the trainer).
I don’t spend that much time on bike maintenance at all - but I do wax the chains and don’t ride an MTB.
This is just speaking for myself, but I had just as much cycling enjoyment when I had one A bike and one B bike, as I do now with four A bikes. I didn’t experience burnout or repetitive motion issues, but of course, YMMV.
I’m a huge sucker for the latest tech with an awesome paint job and kickass components/wheels, but when I think back to my most cherished experiences, it’s never really about which bike I’m on. It’s about being on the bike at all, seeing cool stuff, or being around people with whom I enjoy being.
This is why I like my current gravel bike as much: It reminds me of the best experiences, great tours and lots of good time.
I’m also a big fan of the latest technology, nice looking bikes and like to compare different things. Every time I sit on my carbon bike I think “nice”. However, you only notice the difference to the aluminum bike if you ride them directly one after the other.
You said your old aluminum gravel bike is a lot of fun… I bought a new fancy carbon gravel bike with the fancy gravel geometry and hated it. It’s now my trainer bike. My old aluminum cx conversion is much more fun to ride outside - it rides more like a road bike so is faster on the flats and climbs, or at least I think it is.