"...I heard a long time ago that generators should be cranked up every month or so..."
Any internal combustion engine should be run from time to time. You would think that the hospital maint folks would know that...
During the 'canes of 2004 our local Hospital's generator system was composed of something like three generators. When the hospital installed them circa 1969....they never had them ever turned on. Only one of the generators actually worked. Apparently no one had ever changed out any of the oil or any of the diesel either! They just had enough juice to run all the emergency systems and nothing more.
Since then they ripped it all out and built a 3,000 square foot concrete block building on a hill across the street that houses two MASSIVE natural gas fueled generators that apparently will run off the city gas, which is pumped locally from a well and in the invent of a power outage the city gas companie's own generators can fuel the pumping system.
We'll see....
I start up my geni once or twice a month, personally.