ii) how do you get through 5 frames out in a standard human lifetime anyway? Racing & crashing? Or are you incredibly heavy and/or careless? Or very bad at choosing frames that suit you?!
I can't speak for Ian, but in my case
I bought bike 1 in 2007 new. A Shogun Torsion cheapish full-suspension bike which I loved and upgraded most of the parts on. However, because I was using it for commuting as well off road, I kept wearing the bushings out, to the point where the rear triangle would "snake" as I peddled.
So I bought a second hand hardtail frame (GT Avalanche II) for £20 and took all the parts from bike 1 and put on bike 2.
I then upgraded the wheels on bike 2. However, these only lasted just over a year because I didn't check the max weight on them and cracks started to appear in the rim of the rear wheel. I sold the front one and had a brand new set built at Merlin
After a few years I noticed a crack in the frame around the headtube. No problem, I just bought another second hand frame (GT Avalanche 3) and took all the parts off bike 2 and put on bike 3.
However, the frame of bike 3 only lasted six months, before it developed a crack around the BB shell and downtube.
Fed up with second hand alloy frames, I bought a brand new steel hardtail frame (One One Inbred) and took all the parts off bike 3 and put them on bike 4
iv) at what point does an 'existing bike' become a 'new' bike? Surely if you have bought 5 new frames and various other components then you've effectively bought at least several, if not 5, new bikes - just piecemeal rather than in one off-the-peg package?
In my case, the only time the bike was new was at Bike 1, even though Bike 4 was a brand new frame, everything else has been replaced at some point.
iv) if answering no to the above, does any single original working component somehow retain the spirit/isness/authenticity of the orignal bike?
I'm not sure.
The oldest part on bike 4 is the brake rotors, which came from bike 1 when I upgraded the brakes to BB7s. I really should have changed them a long time ago, but, perhaps subconsciously, they do retain some sentimental value?