In our area, many folks recommend running your hives in either a “2 Deep” setup (1 Deep on top of another Deep) or a “3 Medium” setup (3 mediums, on top of each other.) I am not 100% sure where this recommendation comes from, but I do know that it was the primary push when I started beekeeping.
I spent several years running the Deep and the Medium setups mentioned above, but found them lacking (each for slightly different reasons – perhaps a topic of a later post!) By accident (lack of equipment at one time!), I ended up with a Deep/Medium setup (1 Deep on bottom and 1 Medium above.) This hive did great! Of course, I realized this could have been a freak situation, but I started to convert more and more hives to this setup. Year after year, those hives continued to drastically outperform (both in Winter survival and especially honey production) the hives with the traditional setup.
Today, nearly all of my hives are a Deep/Medium setup and have been that way for years. This setup works very well in my area, central Virginia. I am not sure what I try to “figure out the bees”, but it is my nature (despite frequently finding out that I was WAY OFF course!) Since I find most hives with both brood and honey (from the previous year) in the Medium during late Spring, I have come to the conclusion that the bees really just need a bit more than what a Deep can provide. They really do not need the entire Medium, but they need more than just the Deep. So, the Deep/Medium setup works great for them.
Finally, I must add that this setup works great if you use only Medium supers for your honey. This allows you to swap out frames when necessary, to manage various scenarios, without missing a beat.
In conclusion, I always recommend experimentation to others. You may find that a different setup works even better for you. But, I am currently sticking with the Deep/Medium. My losses continue to be substantially less than the average and I end up with more honey than I need. All good:)