Pretty sure I fall in camp of not using it properly.
I did do the stability check when I first got the meter and seemed ok. I don't calibrate every brew day. Probably calibrate 6 times a year or so. My meter reads hundredths but I am happy if my mash is within one tenth of target pH (I normally target 5.4 and don't worry at all if I am between 5.3 and 5.5, and will just add a little acid if I am over 5.5 and don't remember last time I actually came in below 5.2).
I am using the red Hanna pH meter that was tested by AJ (or Martin can't remember but I think AJ) and was found lacking because it has a timer that can stop the measurement before it reaches stability. I've found that by lifting the probe out of the solution when the clock icon goes off, and then putting it back in the solution, it will restart measuring, more or less from the last value, and ultimately zero in on a value. As my bulb has aged I have found it takes longer to reach this value and I may need to lift and restart the measurement 2-3 times before reaching stable value.
Is this proper? Nope guess not. Is it working for me? I think so. Considering replacing the bulb but not in a hurry.