A. There's no steadfast rule on this, but if you have a lot of cigars in your humidor with little space between them, it does help to rotate them from bottom to top every couple of months. The size of the humidor compared to the number of cigars in it, overall circulation, temperature, and RH also factor-in as to how often you may need to rotate your cigars.
If you're the type of collector who removes the cello from their cigars before putting them in your humidor, be careful handling them so as not to tear the wrappers when moving them around.
The thing I like about rotating my cigars is, I always find something good to smoke that I forgot I had. | 
