Thinking abut it, I ride so relaxed, at any speed, that my arms/wrists/hands almost never get tired or sore, even on consecutive 600km plus days. The fact that I am very light on the throttle and brakes 90% of the time also make tires last longer. (More money for riding) I sit more than 90% of the time even if road is technical or sand. I basically only stand if I want to attack the corners and then I'll be heavy on brakes and throttle as well or if road conditions REALLY require that.
In my books you don't need to stand under 'normal' riding speeds. It is a mental thing as standing you 'detach' yourself from the bike and do not feel how 'alive' the bike is. Traction, G forces centrifugal forces are all linked to the speed you travel. I don't even notice the bike underneath me anymore. Standing WILL ALLOW the bike to react quicker on inputs while standing as it is now a separate 'moment' in the inertia equation which have POSITIVE and potential safety effects.
II DON'T SAY YOU DON'T NEED TO STAND. Just seen a few spills where 'too much standing' caused tiredness and the resultant 'oops'. Most riders I've seen who almost never stand also ride slower to accommodate.
Ek is 'n luigat so ry maar so sit sit.

Adie