Being a successful beekeeper
I heard someone recently say: "The secret to being a successful beekeeper is to have at least two and a half hives". The thinking behind this statement is that you should always have one spare hive and one on the way.
Let's face it, while it's possible for undisturbed colonies to endure for many decades, queens do occasionally fail and hives may also fail to successfully requeen.
The risks increase when hives are being managed by beekeepers. These hives do need to endure periods of stress after being split and we need to be mindful of giving them the best chance possible of survival. This means making sure a hive is very strong (full of stores and with good bee numbers) before we split. Also, keeping an eye on the progress of a hive after a split will go a long way to ensuring the survival of the colony. If one half of your split is struggling and looks like it will fail (low bee numbers and greatly reduced foraging activity), having a strong spare hive may allow you to intervene.
Having more than one hive also allows you to compare activity between your hives at your locale and in your conditions to determine the relative health of your hives. If one of your hives is showing very little activity and the other two are very active, this could a warning sign that something may be wrong.
So, I guess the take out from this is that if you want to start managing your hives by performing activities like splitting and honey harvesting, having at least two and a half hives is a very useful thing.