Last night, while sitting in a totally metal chair (with metal armrests), I opened the compass on my Iphone. The compass rose was completely whacked, showing east as north, etc., and occasionally flipping 180 degrees from that. Thinking about compass calibration on my Phantom, I rose from my chair. When I got about two feet away, the compass rose spun the right way and all was normal. If I moved toward the chair, there began a very slight deviation at about two feet, getting worse the closer I got. This is a pretty large chair so I started thinking. I put my large key ring in my free hand and moved it closer. It didn't affect the compass until it was less than 6 inches away. This makes me think that all the advice about leaving your keys, phone, watch, gold teeth, etc. behind is a bit of overkill. I can see if you wear a big watch and that's the hand you're holding the bird with when you calibrate but other than that, I'm beginning to think its mostly mass paranoia. When I calibrate, I have my keys, a metal belt buckle, my phone in my pocket, a bunch of change in my other pocket and the RC with Ipad mini 2 in the hand I'm not holding the bird in. I've never had an unsuccessful calibration and never had a problematic flight (except when I took off from a metal dock but that wasn't a calibration error/failure, that was "an idiot taking off from a metal dock" error). So, whatcha think? Agree? Disagree? Rather have a beer than discuss it?