1. I have been living with bees for less than three years. The bees, on the other hand, have been living with bees since the Cenozoic era. Even drawing on as much of my species' bee-lore as I have been able to glean in less than three years, the chances of me knowing better than the bees what's good for them is slim tapering to non-existent.
2. Interference risks compromising their health. As for all good things (Schwarzwälderkirschtorte, Pilzdorfpuppenhaus*), the lingua Germanica is on top of this issue, having coined the untenably lovely word, Nestduftwärmebindung. It describes the bees' capacity to keep their nest at a cosy, brood-supporting temperature, more or less irregardless (as they say) of external temperature fluctuations. If we pull open the hive, the warmth disperses and the bees have to work harder to get their babies warm again. The "duft" bit of Nestduftwärmebindung refers to scent, and that gets dispersed too, so hello endemic wax moths, small hive beetles, European wasps, and other bees looking to nick some tasty honey, who all get an extra good whiff of wide open beehive. And finally (or probably not finally, but enough for now), there's a range of bee diseases that are best understood as diseases caused by beekeepers. If there isn't a word for that, then German really needs to get onto it. The truly revolting American foul brood, for instance, is most often introduced to a hive by a beekeeper who picked up infected wax from one hive, didn't clean her tools, and then brought those tools to another hive.
3. It's better for me. Despite there being fifty thousand stinging insects living not ten metres from my back door, I haven't been stung for a year (and when I have been stung in my short beekeeping past, it's because I've been poking around in the hive). Mellow bees make for unstung mammals, which, given the density of mammals (esp. humans) in this here supurbia, seems a good combination.
There are, though, about four times a year when we do need to interfere. And one of them is when this happens:
a bee with her pannier-bags already swollen is contracting polyamorous marriages between almond-blossoms like there's no tomorrow;
the lavender and the rosemary throw an early party;
the tagasaste in the park is indecently floral.
When these chaps start flowering, and the peaches and plums are all on the cusp of budburst, the apricots not far behind, the pears and apples ready to bring up spring's rear (sotospeak), we know that the bees are perhaps a week or two away from bursting the seams of their accommodations -- and if that happens, they'll accelerate their spring swarm (where the queen takes off with half the workers to find more commodious digs). Swarming is mostly a good thing - it's the way the superorganism reproduces itself - but when our bees swarm, we want it to be because they're happy and healthy, not because they're out of room.
So, yesterday, in the rare late August warmth, we added an extra empty box to their stack. We put it underneath the existing boxes. Bees prefer to store honey high in the hive, and keep their brood lower down - this, I guess, something to do with temperature control. Putting the empty box underneath the existing ones encourages the bees to expand their brood-rearing downwards, thereby vacating the existing brood cells, so these can be filled with honey. As the formerly-brood-now-honey-cells move to the top of the hive, we can harvest spare honey, and that way we take away the scungy wax that the brood was reared in twelve months earlier. The comb that's been used for brood at some stage always has cocoons in it, which we render and filter out of the wax (and a delightful process that is, too). When beekeepers keep adding boxes to the top of the hive, and not to the bottom, they get gorgeous pristine honeycomb, cocoon-free, but the bees are forced to keep laying eggs in the same cocoon-lined cells, and as successive cocoons accumulate, the cells shrink.
So. In short. The bees now have plenty of room, just in time for the imminent Spring nectar-flow; their hive is right underneath our generous Japanese plum, and I can imagine them eyeing it off as lasciviously as I am; and I've had my spying-inside-their-home fix for the quarter, much to their collective exasperation. There was, you'll be perhaps horrified to learn, a minor plague of earwigs living in their roof and a small slug in the uppermost box. These guys aren't really problems for the bees, but I violated my own the-bees-can-sort-themselves-out rule, and de-slugged and ex-earwigged their house for them. Which is more than I've done for my own house lately.
* possibly not a word