Yeah, the 'travel a certain number of miles' requirement has been dropped in newer models such as the M3. It's possible that they've even removed that requirement from M2 firmware, but I can't confirm it.
The M2 also requires recalibration of...
I really don't believe most M2s have this. Mine doesn't and I've never seen a rash of reports on these boards about it.
It will (and has) asked for calibration every time that I've moved HP more than a certain distance (50 miles I think it is)...
During this 'compass needs calibration every day' period, has you always been working in the same general region? Did it keep happening after moving far away from that area?
I'm just wondering if there is any kind of interference in the area...
Just as an aside, are we no longer heeding the wisdom of never flying on a half-depleted battery (fly half of it one day, fly on the 2nd have the next day)?
Flying half-depleted batteries were once one strong possible reason for power failures...