How often do you recommend you do each and specifics on how to for those that do not know.  

hi
i did it once after fw update and then no more, look up my thread on setyp for noobs i ve explained the best way imo for imu cal

It's recommended to do compass calibration every time when you flying in a new place. cause magnetic environment in every location is different

The DJI's app for android suggest me every time before flight to calibrate the compass.