I didn't change anything, but I changed everything.
I rode my Coda Comp as-is for 8 years, while I learned what I actually wanted in a bike. When it came time for N+1 recently, the only logical choice for me was a new Coda Elite. But, contemplating things, I realized I'd have to change most of the bike off the top. They've gone downmarket to keep it price-relevant. I'd have had to change out the entire drivetrain. I don't need a Triple, so that's hauling wasted weight. I wanted better ders and crankset, so they'd have to go. An 11-32 9-speed was irrelevant at both ends; a 12-28 10-speed gives me more usable cogs where I need them. $25 hubs won't cut it with a bike I ride hard in all weather, so the rims had to go. No need for an adjustable stem, so that was excess weight which had to go. The rear disc was extra weight unnecessary on a road-oriented ride. I didn't even like the darn grips.
So, by the time I was done with a Coda Elite, the only remaining original components would basically have been frame, fork, front brake and bar.
I kept my original Comp frame and am hanging all-new components on it instead. Nothing but the frame stays. The downside is, I have the price of a Coda Elite just in the wheels and crankset, but by the time I was done with the Elite I'd have had in excess of $2000 in it anyway. And my Comp has a unique unpainted polished/clearcoated steel frame that I haven't seen before or since - it must have been a
bear to produce - so the end result will be a unique ride where every bolt and nut is precisely what I want.