Fork Spring Replacement Interval

I'm still a few months away, but this fall I'll be replacing my steering bearing. Since the whole front end will have to be removed, I'm trying to think of other things to do at the same time. I'm already looking at bar backs and I started thinking about the fork springs.

Is there any standard time/mileage interval for replacing fork springs or are they life-time products? I put in Progressive springs about 7 years and 50k miles ago. They feel fine but that is the kind of thing that could degrade slowly over time and not really be noticed.

Any thoughts?

For the stock springs, BMW specifies a minimum length. I'm not sure about the Progressives. YOu may want to see if they have a similar measurement.

Hmmm....
Good question, Progressive's website only says they'll warranty the springs for life. I wonder what would happen if you sent them a pair and asked for new ones 'cause the old set wasn't "springy" enough.

Steve