Since I am only a second year beekeeper, I worry about my hives dying. I have no resources to help out if something goes wrong. If I lose a hive, it would put a new beek like me with only two hives in a hard place. But I went to the BeeFest 2020 this past weekend, hosted by Jim Altmiller's (sawdstmakr), which was free, and I learned so much about beekeeping. It has made me so much more confident.
I was intriqued by the idea of a queen castle.
I can build a simple box with a board(s) in the middle, and in each compartment I can place some resources and a brood comb (with a queen cell, or grafted queen) and create a small colony of bees in each. Then, as they grow, I just pull resources out of each compartment and add it to my two main hives, which strengthens them. Meanwhile, the little nucs rebuild again. Also, if one of my two main hives fails, I have these other small nuc colonies. I can just move one over into the empty hive. This is a great idea for someone like me, with limited space and just a few hives.
I suppose those of you with larger apiaries just swap out resources from amongst your hives?