I like to use as much varied techiques as possible for bringing out different tonal qualities of the piano. For sFz I like to think of throwing my hand at the keyboard (it produces an accent that is not harsh); staccato can be bouncy, clippy, springy, crispy; legato I could project like a singer, or be more subdued and work with color more; impressionist music I use a lot of the finger pads - caress the keys like you would your lovers skin (something that my teacher was told); for contemporary music I can use brute force with knuckles, fists and elbows.
I like to use as much varied techiques as possible for bringing out different tonal qualities of the piano. I adopt quantum's policy on this too, although I am probably more cavalier still. In years gone by I used to concern myself about which positions and movements were "correct", largely based on the faulty assumption that one correct way actually exists. Nowadays I don't think much about my movements at all unless a real physical problem occurs, and that doesn't happen very often. The result is that I intuitively end up using all sorts of positions and movements, each producing its own type of sound. I don't think down to the level of entering and exiting notes I'm afraid. Perhaps if I were younger I might but I'm getting past thinking at such an atomic level. I always operate on a meta-level these days and let all that take care of itself. By and large I'm producing the sounds I want to. To start worrying about nuts and bolts at my age might impede the flow of ideas now I think.