Okay. So I'll admit I calibrated the compass every time I went out to fly even if in the same location. Even the FAA now gets in on it as they say to recalibrate the compass before every flight with their Part 107 sample checklist. And one of those steps is to calibrate the compass... However DJI in their operator's manual (version 1.8 (Phantom 3 Advanced) now says: So now I only calibrate as directed which is also included in the documentation.