If it's the right chair, it doesn't take too long to get comfortable in it.
I can't sit on my bum very long in a movie theater seat, and when I'm directing, I always want to move the camera or edit.
I have very bad posture.
If you ride a horse, sit close and tight, if you ride a man, sit easy and light.
For us tall people, the whole key is that your hips and your knees should form a right angle when you sit down. That's where backs and hips get to be problems for big guys.
I had something called the back of the chair test. Where I sit, we don't sit like you and I do. I can see a sliver right behind them and they come out and they sit like this like god students and they don't touch the back of the chair.
Prolonged sitting can cause stiffness in your lower back.
Slouching or leaning back may send the wrong signals. When you sit down for a formal interview, lean forward to show interest and active listening.