The machines were designed to run practically forever. They almost never were unplugged when in use. What kills the compressor is letting it sit for a long time unplugged and unused. After sitting for a long time and now being put back into use you may have some issues, but if it's been running and cooling for three hours you're probably good.
Now I have to admit that I plug and unplug my machine all of the time because they suck power like a small town, and so far it keeps running.
Is your refrigerator running?
You better catch it!
(That's an old telephone prank call we used to use, just like "Do you have Prince Albert in a can?"}
