Granted, I would take into account the age/physical condition of those who express their reservations about sitting in a theater for 11 hours. When you're young (in your 20s or below, your body can withstand much more in terms of endurance of inactivity. When you get older, the body can betray...
Yesterday I had to move around in my seat, and for a few times, I felt like I was auditioning for the role of Gollem (movement-wise) as I tried getting into comfortable positions from time to time to keep the blood flow flowing, like turning my back to the screen sideways a bit, or being splayed...
After watching TTT:EEE this afternoon, I now know that you could not pay me to sit in a theater for 11 hours for the LOTR trilogy. It may seem like a good idea at the time, but once you actually do it, I think the cinematic fatigue is going to impede many people's enjoyment of ROTK.
Your health is more important then missing bits and pieces of a film. If your bladder says it's gotta go, heed it. Candy might help in staving off thirst (I usually eat Skittles or chewy Spree), but it's bad for your body to not have fluids for extended periods of time. Perhaps just sip your...