I would like to be able to read a colony better before I open up a hive. It has that feel of long experience of observing bees. The little booklet by H. Storch is sometimes held up as the ultimate goal in this area. However, Ken Basterfield dismisses it as a work of imagination and wishful thinking.
I've seen people really stuck for words (on one occasion in a very public setting) when asked what exactly they can hope to glean from time spent at the hives before opening. Rusty Burlew has written what I think is a poetic, evocative and realistic account of what you can know and discover before you take the roof off.
'Most of the time you can tell everything you need know by standing near your hive and watching. You know a lot by how the colony behaves, the way it sounds, the way it smells, and the number and type of bees that come and go. You can tell even more by watching what they bring in, observing what they haul out, and assessing their temperament. If you walk by your hive on a summer’s evening and it purrs like an insulated engine room, smells like heaven, and the landing board is clean, why on earth would you open it up and disturb everything? It doesn’t make sense.
'On the other hand, if the number of bees is decreasing, you see dead bees or pupae unattended on the landing board, you detect an odd odor, or your bees are unseasonably temperamental, open the hive. If you see robbers, predators, or leaking honey, open the hive. If you see lethargic, aimless, or deformed bees, open it up.
'Compare what you see on the outside to what you find on the inside until you develop an intuition. It will happen sooner than you think. And in any case, use common sense. No animal wants its home torn apart for no good reason. So before you do it, have a clear idea of what your good reason is.'
See:
Is too much hive inspection a bad thing?