500 would be 5000 km even at just 10 km/h which would be generous (but doable) for a Shimano chain even under roadbike conditions (where this would be roughly 2

500 would be 5000 km even at just 10 km/h which would be generous (but doable) for a Shimano chain even under roadbike conditions (where this would be roughly 200 hours). Mountain bike conditions will increase wear level a lot and they'll probably be a bit faster than 10 km/h as well. I don't know if it is really as bad 50h, but I've stopped mountainbiking when suspension forks ceased to be exotic. It also differs regionally: riding muddy in a place where the air is full of corrosive ocean spray will require far more chain replacement than riding in the Utah rock deserts. If you ride a chain until it stops working you'll probably reach those numbers. But then you will have to replace the entire drive train which is far more expensive. The chain is the cheapest part and replacing the chain a bit earlier than absolutely necessary will greatly increase the durability of more expensive parts. As a little bonus you'll repeatedly get the joy of riding a new chain. Replacing at the right time is cheaper and more enjoyable at the same time.