I ran deeps and shallows for decades, but I eventually converted it all to eight frame mediums. It would have been much easier to buy them in the first place.
Uniform frame size.
"Whatever style (hive) may be adopted, let it by all means be one with movable frames, and have but one sized frame in the apiary."--A.B. Mason, Mysteries of Bee-keeping explained
The frame is the basic element of a modern bee hive. Even if you have various sized boxes (as far as the number of frames they hold) if the frames are all the same depth you can put them in any of your boxes.
Having a uniform frame size has simplified my life. If all your frames are the same size you have a lot of advantages.
You can put anything currently in the hive anywhere else it's needed.
You can put brood up a box to "bait" the bees up. This is useful without an excluder (I don't use excluders) but it's especially useful if you really want to use an excluder. A couple of frames of brood above the excluder (leaving the queen and the rest of the brood below) really motivates the bees to cross the excluder and start working the next box above it.
You can put honey combs in for food wherever you need it. I like this for making sure nucs don't starve without the robbing that feeding often starts, or bulking up the stores of a light hive in the fall.
You can unclog a brood nest by moving pollen or honey up a box or even a few frames of brood up a box to make room in the brood nest to prevent swarming. If you don't have all the same size, where will you put these frames?
You can run an unlimited brood nest with no excluder and if there is brood anywhere you can move it anywhere else. You're not stuck with a bunch of brood in a medium that you can't move down to your deep brood chamber. The advantage of the unlimited brood nest is the queen isn't limited to one or two brood boxes, but can be laying in three or four. Probably not four deeps, but probably in four mediums.
I cut all my deeps down to mediums.
Typically I hear the question, "do they winter as well?" and I say they winter better in my experience as they have better communication between the frames because of the gap between the boxes. Steve of Brushy Mt. used to say there was some research to this effect, but I'm unsure where to find it.
"Friends don't let friends lift deeps" Jim Fischer of Fischer's BeeQuick
The hardest thing for me about beekeeping is lifting. Boxes full of honey are heavy. Deep boxes full of honey are VERY heavy. There may be some disagreement as to the exact weights of a full box of honey, and there are other factors involved but in my experience this is a pretty good synopsis of sizes of boxes and typical uses for them:
Standard 10 Frame boxes
Name(s) Depth Weight full of honey Uses
Jumbo, Dadant Deep 11 5/8" 100 - 110 pounds Brood
Deep, Langstroth Deep 9 5/8" 80 - 90 pounds Brood & Ext
Western Bee Supply 7 5/8" 70 - 80 pounds Brood & Ext
Medium, Illinois, 3/4 6 5/8" 60 - 70 pounds Brood & Ext & Cmb
Shallow 5 ¾" or 5 11/16" 50 - 60 pounds Cmb
Extra Shallow, ½ 4 ¾" or 4 11/16" 40 - 50 pounds Cmb
8 frame boxes:
Jumbo, Dadant Deep 11 5/8" 80-88 lbs
Deep 9 5/8" 64-72 lbs
Western Bee Supply 7 5/8" 56-64 lbs
Medium, Illinois 6 5/8" 48-56 lbs
Shallow 5 3/4" or 5 11/16" 40-48 lbs
Extra Shallow 4 ¾" or 4 11/16" 32-40 lbs
If you want a grasp of these and don't have a hive yet, go to the hardware store and stack up two fifty pound boxes of nails or, at the feed store, two fifty pound bags of feed. This is approximately the weight of a full deep. Now take one off and lift one box. This is approximately the weight of a full eight frame medium.
I find I can lift about fifty pounds pretty well, but more is usually a strain that leaves me hurting the next few days. The most versatile size frame is a medium and a box of them that weighs about 50 pounds is an eight frame.
So, first I converted all my deeps into mediums. It was a huge improvement over the occasional deep full of honey I had to lift. I still got tired of lifting 60 pound boxes, so I cut the ten frame mediums down to eight frame mediums. I'm really liking them. They are a comfortable weight to lift all day long and not be in pain for the next week. Any lighter and I might be tempted to try to lift two. Any heavier and I'm wishing it was a shade lighter.
I'm wondering how many aging beekeepers have been forced to give up bees because they hurt themselves lifting deeps and it hasn't occurred to them there are other choices?
Richard Taylor in The Joys of Beekeeping says:
"...no man's back is unbreakable and even beekeepers grow older. When full, a mere shallow super is heavy, weighing forty pounds or more. Deep supers, when filled, are ponderous beyond practical limit."
I often get asked what the down side of using all eight frame mediums is. There is only one I know of.
8 frame medium vs 10 frame deep = 1.78 times more initial investment for boxes. ($64 for four eight frame mediums plus frames vs $36 for two deeps plus frames)
$512 vs $288 for eight boxes vs four boxes
Plus lids and bottoms ($20)
$532 vs $308 = 1.73 times more or $224
100 hives * $224 = $22,400 which should just about cover your back surgery.
Typically I hear the question, "do they winter as well?" and I say they winter better in my experience as the cluster fits the box better and they don't leave behind frames of honey on the outside as much as they do in the ten frame hives.