I use a 40". If the middle of my monitor is just about eye level, I don't find myself moving my neck vertically very much -- eye movement suffices for vertical

I use a 40". If the middle of my monitor is just about eye level, I don't find myself moving my neck vertically very much -- eye movement suffices for vertical travel. If you have the opportunity, though, monitor arms are one of the best ergonomic investments you can make. Being able to reposition the monitor with a touch for whatever position or attitude you want helps reduce fatigue enormously.