Re: How often to requeen
There is an argument that it all depends on how heavily the queen has had to lay. In equatorial regions (latitude 20 degrees N to 20 degrees S) queens are rarely good for more than one year. This is because they are called on to lay eggs year round. Further north (roughly from the gulf coast of the U.S. to Iowa) a queen may be good for 2 years.
My personal experience is that queens should be replaced yearly if you want an optimum crop of honey.
NW Alabama, 47 years, 22 colonies and growing, sideliner, treatment free since 2005, 14 frame square Dadant broodnest