A brief response to the original question. ... it depends ... Much depends on the business model, specifically if have a program for raising queens in-house or ifbuying/importing queens.
Basically for the in-house queens:
- Let the bees bee bees as best they can bee
- Purposeful re-queen only the hives that have to be. The decision is based on colony health and performance, temperament, and the timing within the annual cycle of the seasons.
- In large apiaries, each queen is not monitored nor managed at a detail level. Each hive is assessed and managed holistically at the colony level. The queen is just one member of the colony, albeit the most important one. Hive management decisions are made within a minute of cracking the lid, at the hive level, and the beekeeper moves on.
- The bees will often re-queeen themselves without the beekeeper even noticing. In good colonies, good genetics, only when queens are marked will the change of reign be noticed. In the poor genetics, the poor colonies fall flat during a supercedure period and these are promptly culled by the beekeeper.
- In a commercial environment the queens are pushed hard. She is done and gone in 2 years. Her lifespan typically goes like this: Raised spring/summer 1, winter 1, production summer 2, winter 2, spring 3 she is split / superseded / replaced at least 6 weeks before main flow season. If she is exceptional, she will survive the spring split and go on to rebuild to a production level hive for the summer. By the fall she has swarmed or been superseded or the hive has gone queenless and falls flat in September.
- Commercial hive management is merciless, generally. There is no such thing as -wait and see- stance taken with a hive. Exception being in small mating nucs. Queens and colonies are culled ruthlessly. Only the proven prominent get through to survive.
- This following comment is depended and skewed entirely on the business operating model. In my personal practice/experience, re-queening commercially has become quite rare. The practice is to cull, combine, replace at the colony level. This is done through a continuous program of stocking nucleus colonies. The method of re-queening by (a single bug in a cage) has become a rare exception applied to a very limited one week window in mid-April in desperation to backstop a season against unusually heavy winter losses to both the main apiary stock and the nucleus colony stock.
Hope that helps, in some way.