FYI Norcold Refrigerator
Not knowing for sure, I wrote to Norcold and asked if hurt the unit to run it all summer since I camp about every other weekend on the average.
They answered that it was a personal preference and that running it continually didn't take away from the life of the unit.
2012 F150 F/X 4, 6cyl EcoBoost with Max tow pkg
2013 Rockwood 8280WS 5th wheel
2006 Sunline T1950
2004 T@B T-16