I've researched this topic pretty extensively and I have yet to find a definitive answer. Of all of the forums, this one seems to be most interested in humidor "climatology" (Hello, @PigFish, I've ready many of your posts!) so I thought I'd pose this here.
I'm debating on whether or not I should keep air circulation fans running constantly in my humidor. I'm aware that some pretty much universally agreed upon potential effects/side effects of doing this are:
Raised temperature due to heat generated by fans
Higher electric bill
Better distribution of temperature/humidity
However, there is one that always seems up for debate: "it will dry out your cigars".
I am going to make an educated guess that while air circulation may catalyze/exasperate an existing problem in a humidor (leaking humidity, etc), it doesn't directly "dry out" a cigar. I imagine if a fan is running and is directed at one particular cigar, that one cigar may experience changes quicker than other cigars, but whether it gets "dried out" would be a function of how much humidity is present in the humidor. Therefore, assuming a humidor is properly sealed and humidified, and the temperature is stable and within a healthy threshold, constant air circulation poses no risk of "drying out" cigars.
I suppose I could experiment and find an answer on my own, but I'm quite afraid of destroying my cigar collection ?