One thing I internalised when speaking with a physiotherapist is that part of avoiding serious issues is making sure you don't stay in the _same_ position for too long. One good ergonomic position is an excellent start, but changing your position several times throughout the work day is even better. This apparently helps avoid building up strain and inflammation in pinch points, balancing out the fatiguing action more.

I have found that my Ergodox allows me to juggle my keyboard halves around the desk at different angles and spaced apart at different widths, and I can put my trackball either to the right of everything or between the halves. It's a single anecdote, obviously, but I have been able to make my ulnar and carpal entrapment issues mostly go away by finding better positions while working and by not staying stuck in one posture or position for too long at a time.