Isn't it summer? I feel like these threads are usually relegated to other, colder seasons.
The answer is: we will probably never know. You would have to put the drivetrain on some sort of Friction-Facts-esque measurement device, repeatedly testing while gradually wearing the entire setup down to the point where all of the parts were knackered... and honestly, I doubt there would be much difference. New cogs and rings shift better. But for simply applying power in one gear, stuff can be really worn and you might never notice. I had a chain wear well past 1% and absolutely could not tell. It was an expensive oversight, but the bike didn't feel any different at all.
__________________
