Like Fox, I have a tee in the bottom of my 80 gallon tank and I drain it every time I go into the shop. The drain line is big enough that it will hold all of the water on most occasions without it actually sitting in the bottom of the tank. I also change the oil ever year.
I also use to leave it on automatic a lot until I came home after being gone all day and came home to find the small line to the cut off switch had come loose and the compressor had run for sometime from the "feel" of the air.
Yep, sometime we have to learn our lessons the hard way........now I simply cut it off every time I go out the door. That was about 3 years ago so not much harm must have been done. Its still gittin it today!!
Learn from my mistake!!!