Dynamike: Everyone develops their own technique I guess. For what I do, any more than half a stop either side is usually too much. The flowers average 10mm across and have extremely delicate shades of colour and translucent areas which require precise exposure. Under-expose slightly and you lose detail, over-expose slightly and the highlights burn out. I've found recovering from the RAW isn't as good getting it right on the camera.
It's just a hobby, but I regularly get requests to buy photos. However, I just give them away. DoC is using quite a number of them on information boards, they're in some books, Te Ara Encyclopedia of NZ, a couple of Museums including Te Papa, Forest & Bird occasionally use them, saw them on a TV3 News item once, and I built a website on native orchids.
Fair enough, my requirements are quite different from yours, and I find within a stop either way works fine when you're using modern software. Overexposing is more of a problem than underexposing. Overexposing the sensor limits and information is gone, underexposing you're just not making full use of the dynamic range to show colors off to their best advantage, and you get more noise.