Question: Is it better to stand or sit when painting?

It depends on what you are trying to accomplish and how you feel. A few years ago, About.com conducted a poll to see what most artists preferred. At the time of this post, the responses were evenly split between sitting and standing (most or all the time).

Those artists that prefer to stand are often looking for greater energy or expression. As Michael Johnson states, when standing "...you can put your whole body into each brush stroke; [and] ...you can more easily take several steps back to view your work in progress." An artist does have greater freedom of motion when standing. So, if you are working in a loose expressive style, it might be easier to paint standing. However if you are painting detailed or delicate images, a seated position is probably more conducive.

The only other consideration I can think of is comfort. Although I can stand for a time, it is difficult for me to stand at an easel for an extended period. And, if you are painting from life you don't want to change your point-of-view mid-session by sitting. A possible compromise is to paint seated on a high stool. This requires less stamina of the artists but is very similar to standing.