I use set fingerings for the more common playing forms. However, once chords and scales get beyond the basic, that is to say I'm often creating them as I go along, it seems to me that, unless the position is really awkward, memorised prior determination of fingering is largely more trouble than it is worth.
Lostinidlewonder's point about stopping the habit of thinking of any playing form in one position, I consider most important for improvisation and playing generally. It is just as easy to think of a chord or scale as a usable subset to select from "at a glance", as it were, and continually varying the way its component notes are used. It doesn't take long to develop this mode of thought. It's not difficult and the rewards in terms of variety of expression are well worth the trouble taken.
As to fingering, I do in fact often use all five fingers spontaneously and equally - hardly ever in the same way twice though. Admittedly I do use the "microsleep" trick very often. It is harder to play continuous, rapid runs and figures than the same things with even one note omitted, no matter how tiny the gap. So if important events in one hand are made to coicide with microsleeps in the other, everything is a lot easier (I'm talking about improvisation, not playing written pieces of course), and rhythmic impulse is heightened considerably. What may initially seem a cheap trick is actually a pretty fertile source of ideas at the piano.
Topic: Pentatonic scale fingerings -- Major and minor