In my teens and early 20s, I went through a lot of bikes - a couple 1-speed coaster brake bikes, a rickety 3-speed, the indestructible Schwinn Varsity, the Centurion Super Elite that was my first "real" bike, several broken Hypercycles...
But starting in 1982-83 or so, that slowed down and I started hanging onto what I had. I've owned my Raleigh Pro since 1982, my Rans recumbent since 1983 (it just turned 40), my chrome Schwinn since 1992, and so on. I may change components and setups periodically (or not), but I'm much less likely to divest a "first string" bike - so they've accumulated. I do have several decent "second team" bikes that are entirely functional but with which I don't have the same bond - all of them are great, but may someday go home with another person for which they're more suited.
I try to ride all of my "first string" bikes (see
Richard C. Moeur - Bike Stuff) at least once per month, and the backup bikes each a couple times per year. Some bikes such as "Boingy Green" the dual-suspension mountain bike are optimized for one purpose, and don't do well for other tasks, while the Bike Friday is great for when I need a folder, and the recumbent is comfy in street clothes. Other bikes do occupy similar niches in terms of speed, weight, and carrying capacity, but are optimized in other ways. For example, my fancy aluminum-frame cruiser and my taped-up commuting cruiser have nearly-identical carrying capacity, lighting, and travel speeds (the aluminum one being faster), but I'll choose one over another based on distance, security of parking at the destination, etc. And my big-basket chrome cruiser is much less fast, but great for yard sales, rides to the store, and bombing around the neighborhood. The Nashbar aluminum cruiser is "first among equals" and usually gets the most miles in a year, but often doesn't have the longest one-day mileage (those are on the racer and alumispeedy). The tandem is another story - its speed typically depends on how motivated the APU is, but since I have no one in that role at the moment (wife has bad knees and son's uninterested), it's hung up UFN.
So I tossed together this profoundly unscientific chart roughly showing how all the primary bikes somewhat relate to one another in terms of speed vs. capacity. It's a start.
