6.5 years of full-timing, so my ref. is on ALL the time - and I open the freezer door quite often to get ice cubes. I've found it necessary to defrost about every 2 months. My ref. is in my slide, so I have an upper & lower vent in the sidewall. I've been thinking the air circulation with this set-up may not be as effective as one on the sidewall & one on the roof. That may be why my freezer frosts up so quickly, but that's just a guess.
2013 Eagle 266RKS
2011 Ford F-150 w/3.5L Ecoboost & H.D. Tow Package