Depends on sprocket wear, chaingang produce treated sprockets which are designed not to wear, and would last probably a few chains. I dont have a chaingang sprocket myself, incase u think im plugging their product or something.
Maybe the price would work out about the same cos of the longer life, and u have to change it less.
incase ur interested
http://www.chaingang.com.au pricey, but maybe its justified?
But chaingang seem to make only rear sprockets? but wouldnt the engine sprocket be more likely to wear, fewer teeth transmitting the same force at greater speed, seems to me like the majority of wear on the chain would occur at the engine sprocket, not at the rear. Making the extra expense of the chaingang sprocket good to make ur rear sprocket last longer, but not your chain.