Just get a couple of Sram PC850 chains and a steel ruler. Measure chain twice a year or more often. If Pin-to-Pin over 12" gets up to 12-3/32", replace it. Sometimes I just replace at 1/16, since 8-speed chain is so cheap.
https://www.universalcycles.com/shop...12&category=61
http://www.amazon.com/10416-Westcott...22+steel+ruler
I'd clean drivetrain once a week in the winter, if you can find the time.