Regarding chain life... there is no set standard for chain life. There are many factors involved that contribute to chain wear. The Hours a machine runs may not necessariy be an indicator of chain life either. Chains can last for a long time, yet can wear out sooner than anticipated.
The best thing to do is invest in top quality chain, like Tsubaki Omega, as an example. There are others as well. Low-cost, cheapo chinese chain should be avoided like the plague.
Keep them lubed as well.
Stand for the Flag. Kneel for the Cross.