I usually try to send mine in once a year to get a battery swap and re-calibration of the slope (yes, I know you can do this at home, but so far, I have been too lazy to go through the process or ensuring standardized mass accuracy, etc.). I try to do this after my last race of the season in order to ensure time away is minimally disruptive as possible.

Once I thought I would try to get away with going longer- turns out my SRM battery died mid-season, and I needed to send it away for a really quick swap before a race. I won't do that again... :)

Thanks a lot. Very interesting that you said the slope should be recalibrated. Per the instructions, I know how to do this. But, are you saying that the slope actually changes over time and they need to figure out what the new slope is? So is what you are talking about not in the instructions at all, and they actually have to calculate this? Or is it simply the same number as the old slope and it just needs to be recalibrated into the device?

Thanks again,
Chris

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Running is the best source of fiber that I know of...