question on pH probes

[ctreefer]

I have a milwaukee pen style pH meter (sharp ph51) and I'm not sure how I'm supposed to store the meter (probe) when not in use. The directions say to add a few drops of storage or ph 7 solution to the cap before putting it away. I tend not to check pH very often (months sometimes) and everytime I pull out the meter the probe is dry and way out of calibration and it takes hours to get the probe back calibrated. Those few drops don't seem to cut it. Maybe this means I need a new probe as its been about 2 years probably. Does anyone store the probe in a full solution to keep it wet at all times? How often do you calibrate and is it common for the meter reading to fluctuate wildly while holding it in your hands to check a reading?