I have just bought a new hybrid to cycle the 15 mile round trip to work.
What is the best way to get the maximum life out of the drive system.

On my last bike i used to run two chains and swap them every 300 (ish)
miles, degreasing and re oiling the removed one. I got a couple of years
(approx 7000 miles) before having to change the whole lot.

Does this sound like a reasonable way of doing it, or is it better to just
keep renewing the chain every ??? miles (suggestions appreciated).

Seems like an awful lot of work for minimal savings. I've found that a
normal chain in normal use, not cleaned as often as it should be, is
generally good for 1500-2000 miles. Replaced that often, the rear cassette
is usually good for 5 chains (so up to, say, 10,000 miles) and the
chainrings up front often go further than that.

There's nothing at all wrong with keeping your bike in tip-top shape, and a
clean drivetrain is a great way to do that. And if you really enjoy working
on your bike, great! But you are spending quite a bit of time removing &
cleaning chains, and it appears that saving money isn't the payoff.

Nevertheless, a clean and lubed chain *is* a happy chain!

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com