I've had a set of Fox Vanilla forks for a while (I think they're 2004 models) and they've been ridden pretty solidly over that period. I've noticed lately that they seem to have less preload than they used to, and have been going through their travel faster than they used to.

I know it's a pretty weird kind of question, but do fork springs 'wear out'? Anyone had a similar experience?

In theory coil springs will 'soften' time with use, a six year old spring will probably have lost some stiffness.
The oil in the damper will probably be past it's best too if you haven't serviced them in the past 12 months, which will have a bearing on the compression damping leading to them going through the travel more easily.

Thought it was a bit weird, but was theoretically possible. I've recently serviced them, with new oil etc, but didn't make much difference. Might have to try to procure a new spring…