It's come to the time where I need to replace some drivetrain bits (currently 2x9) and I'm toying with the idea of going 1x10 after surprising myself at what I could get up with a 32t front this weekend. The swap is going to be fairly expensive, and a fairly big chink of that is going to be the cranks (£100 for an XT double).
So my question is do cranks have a lifespan? There's no obvious sign of wear on my current ones apart from a bit of heel rub, but they must be coming up to five years old and I'd sooner replace them before they break for obvious reasons. They've been in pretty much constant use, though they are pretty meaty FSA Gravity jobbies.
So can I use that as an excuse to buy new shiny things?