I've been using a Stages Power Meter on road bike and I've been calibrating every ride post initial FTP test end of August. Prior to my initial FTP Test I didn't calibrate all summer! I've been using the stages for a year now on my road bike averaging 2-3 rides per week. So far I've only had one connection issue and went through one battery. Guess I've been lucky?
I set the sampling rate to 1 sec or 1 hz on my Garmin. By default a Garmin Edge 520 (prob other GPS devices too) have smart sampling. It figures okay, you're holding ~85rpm for past 10 minutes, I don't need to measure cadence as a priority every 1 sec. Data streams are smoother in Strava/Connect/Training Peaks, Garmin uses less battery. But for power you'd get some weird readings or in inaccuracies because it will change slightly every single pedal stroke.
My power display on screen is 3sec Avg. Its going to fluctuate while road riding. Wind, bumps, road vibration. Only time I get super smooth and consistent power readings is indoors on the rollers.
Not sure if these two things will help people having issues with stages. It's been working for me.
My background is not electrical engineering, so there is a 50% chance I'm correct on this. I tried some googling, apparently as temperature increases, resistence decreases. So at lower temp a power meter would give a higher reading than at higher temp? Maybe my FTP was higher back in August because I didn't calibrate. Regardless, I worked with the numbers I got.
End of the day if your equipment is working, be consistent using it. I'm not sure the guage on my tire pump is 100% accurate, but it's the guage I always use. 20 PSI may be 23 PSI on your pump or gauge, but I go off mine and set pressures accordingly before rides and races. Same deal with power meter, 322 W for me may be 300 w on your bike or 330W on stationary bike in gym. But Im going with my numbers and structuring accordingly because 70% of my riding is on the road for training.
Power based training is just one piece of the puzzle, not an end all be all. I agree with
@pearl , I'm not looking for exact or precise numbers here. Maybe if I was going to TT Nationals in Open Men, that 5 to 10watts would make a difference, hence the need for a higher end power meter measuring both cranks or at chainring. I'm doing Cat 1 XC here, and when doing intervals I want to be in a certain range for a certain period of time.
@Norm if the cookies give me incorrect or inconsistent ratios of chocolate chips per cookie can I return them for a refund?