How often should a hive be requeened?
In general, I recommend proactively requeening each hive roughly every 12 months. If you requeened in the fall of the previous year, the fall of the next year is fine.
The same goes for spring. Check out our article on “What time of year is best to requeen hives”. Though there is outdated literature stating every 2 years is sufficient, queens simply do not live as long as they once did due to pesticide exposure, lack of genetic diversity, etc.
It is annoying to kill and requeen a hive that seems to be doing well, but queens can fail quickly, resulting in a lost honey crop, or worse, failing at a time of year you can’t purchase a new queen. During spring splits is a common time to requeen all hives, as it can be easiest to find queens after a split has already been made.