I don't requeen every colony every year. Why requeen a colony with an apparently good queen. Young queens are better, true, but... not every queen you buy or raise is good. So, I requeen colonies tha need it. How does one know? Pull a frame of brood. Beautiful...comb is full and capped. Good queen, right? Maybe not! You should be looking at uncapped brood. Every cell should have a larvae. Oldest larvae should be in the center, with progressively younger larvae to the outside. Larvae age shouldn't be random. Say 30% of the queens eggs are duds, or the queen fails to lay in 30% of the cells on the first time around. She'll go back over the comb in a few days, and lay in the empty cells. Again - 30% skips. Goes over it again, etc. Eventually the comb is mostly capped brood. Before it begins to hatch, it looks pretty good. So, look at the larvae. Compare it to a really good one. You'll see what I mean immediately