I think the obvious answer for longevity of the chain and sprockets is lubrication, but not any old lubrication, the standard built in oiler is not overly successful due to the unavoidable changes in viscosity, the boiling of the chain in Linklife in a no longer needed kitchen appliance deep fat frier has been consigned to history, the aerosol cans of various types might save the chain running bone dry I suppose, but that is about the only good thing I could say about them. For me the complete answer is the latest offering from Scottoiler, fully electronic and programmable, I set mine to the maximum amount of flow before contamination starts to be evidenced on the rear wheel and tyre, just a few spots mind, then just back it of a little until it runs clean, perfect. The Yamaha TR1 (which for me is a modernish copy of a Vincent, Series E maybe) has the best solution for a chain driven bike, a fully enclosed rear chain running in a molybdenum disulphide oil, good for 100,000 miles apparently, I do own one, but have not managed to do 100,000 miles, always to busy riding the Vincent.