My back is usually fine, luckily. Walking every day is helpful, plus exercise and stretching.

Working on the computer for hours is a risk zone. Me and my wife have a temporary setup in a small apartment where we can't fit regular desks, so our PC's + keyboards are placed on top of 2 boxes of books. This saves space but is not great for posture when working, especially when I paint or sculpt with a digital pen on my Wacom tablet/monitor.

Reduce toxic intakes, lift with legs rather than the back. At work, ask for an extra hand if something is too heavy or the lifting position is bad.