I have been working stand up for about a year. My day can include 2-9 hours at my desk. Some days I have meetings or group work sessions that cause me to sit, sometimes I am presenting and can stand, sometimes I go on drives to work locations and get out and walk around. It doesn't matter if I am sitting or standing I despise being stationary in front of the monitor for extended hours.
I weat merrell trail and tough gloves to work(workboots to the field) .
Find a counter stool or cheap barstool to lean against or sit on from time to time(there are sit to stand seats that I would recomend.(during extended hours I like to switch back and forth or take breaks and go for walks. I actually find the more varied I keep my reutine(stand for an hour-go sit in meeting for an hour, go to the field and drive+walk around for a couple of hours, go back and stand and enter information and answer emails for an hour--makes for a comfortable body.
Any body position sustained for too long can become unhealthy so just don't stand there, try to incorporate some movement and position changes into each day. Expect a little soreness if you are not accustomed to standing for long, it passes(if you incorporate the position changes from time to time)
Integrity is what we do when nobody's watching.