Originally Posted by
Wileyrat
You'll lose more money than watts from a worn drivetrain.
This is'nt exactly true with cheap drivetrain components. For example, a chain and casette for $15 each will last for about 4000km before starting to skip, if the chain isn't replaced when recommended. If by timely replacement (say, after 2000km) of the chain you get 3 chains with one casette, you do 6000 km for 3x15+15=$60. That averages out $30/4000 = $0.0075/km in the former case, vs $60/6000 = $0.01/km in the latter.
Cheap crankset for $30 will outlive no less than 2 casettes, more likely 4.
Worrying about the drivetrain wear makes sense only if your cogs and chainwheels are significantly more expensive than the chain.