[cowb0yl0gic]

All of the above/below. It's a complex problem (which I share) caused by a lifetime of habit, and it takes a long-term, multi-pronged/phased approach. A) Physical fitness: proper conditioning will allow you to hold posture for long periods of time without fatigue/strain (this is something you work towards over time). B) Physical environment: everything must allow you to maintain posture without excessive leaning/reaching/craning; don't hold a fixed position continuously, but your base state should be strain-free. C) Habits: take frequent stand/stretch breaks (sometimes I stand up if I am reading something that will take a minute or more; also remember to rest your eyes periodically; look out the window; engage in brief social interation; standing desks are great (alternate with sitting), especially if you get restless). D) Triggers: develop reminders about posture (if I see my reflection from the side or when I'm sitting in front of a TV...; I try to be (not self-)conscious of what an observer would see); when you stretch, use that to "reset" your postural expectation (through repetition, it will become your "natural state", and you will be aware of when you're out of sync with it); if I don't feel like I'm standing up really straight, then I'm not. E) Mental state: if you feel tired, depressed, preoccupied, etc. then you will lose track of all of this; it won't seem important, and you will regress; pick it back up again and move forward (it's about improvement/maintenance, not "fixing"). HTH.