Nike + iPod kit: battery life

I am tempted to get the Nike + iPod kit, particularly since it’s been proven that you aren’t obliged to use Nike shoes - I prefer Mizunas myself. However, the battery is not replaceable in the sensor, which brings to mind the early iPod battery debacles. All Apple says on their store page is The sensor’s battery is not replaceable. Battery life will vary considerably based on use and other factors. I think I will wait and see how many miles people are getting out of it first. Besides, I only really use my iPod when running on a treadmill; when I’m out at Frick Park or on the Butler Freeport Trail I much prefer running sans phones. Must resist gadget…must resist…