Expect a 200 CCA battery to start a big single cyl for 1-2 yrs at most before you have to jump it or top it up on a charger for several min before an outing. Often times, a batt that will no longer crank a big single will turn a twin, for another season at most, but then its ready to be recycled. Lead acid batteries will lose cranking power as the plates sulphate-up over time. Key to minimizing the decline is to keep them fully topped with a 'floating circuit' charger when sitting for long periods or between seasons.
Having motorcycles has taught me a lot about cranking power and the service life of small batteries on big motors. As the kick-starter has disappeared to allow for too many gears (tranny wider) and bulky gov't approved exhaust bling we can't get away with a cheesy battery when relying on electric vs kick or push starting. (not easy with the big twins if you're over 60, btw) I have a rack of 16 AH pulls that are too big to fit onto what they'll still turn over, have been using economy batteries for far too long, and got away from riding when replacing them every year became the pita I wouldn't learn from soon enough. :duh:
Excess cranking power is mostly to allow reserve capacity as a battery ages and loses its original oomph, so what that translates to is years of service. A battery's warranty used to be a predictor of it's useful life, but gel-cel and other newer types are rewriting the rules and lasting longer. TSC seems to have the best deals locally on the newer high-output batteries (>300 CCA ~ $50, etc). IMO, in years of use per dollar spent a $90 battery will outlast a $45 one disproportionally in the same service.
btw: My neighbor showed me how to ruin a fancy Optima (yellow 6-pack looking, in his Polaris Ranger), getting not quite two seasons out of his by assuming it was indestructible if neglected. So, it's still not just what you have, but what you do with it ....
