OK, I want to preface this by saying I think this is going to spark some debate, but hopefully it stays civil.
I've been keeping bees for about 16 years now. Over the past few years I have helped a few friends get started who were interested. One of the first things I have always told them, and remind them of, is "Don't take everything I tell you as gospel. In the beekeeping world, there are opinions on every topic. Continue to talk to other beekeepers and follow sites (such as this one) and other sources and form your own way of beekeeping."
Along the way I have began to think, are there any 100% do's/don'ts about beekeeping? For instance, screened bottoms vs solid bottoms, mite treatment vs natural selection...
Reply with something you think is a 100% given in the beekeeping world. If you are an adamant natural selection person, there will be many who believe 100% the opposite.
Do you think there are any 100% givens? Something that applies to all beekeepers universally, without exception, which would be beneficial to a newbie?