I would say whatever range you find yourself able to stay inside of 4-6" off-hand on a regular basis.

For many folks, inside of 4-6"/off-hand is much less than 100 yards.

Bench/stick shooting is fine, but not always the opportunity.

Sure use the bench to establish that the rifle is shooting well and then start off-hand practice.

For bench shooting, I would think the same inside 4-6" rule would apply only you should be able to obtain 75-100 yards iron sights and even farther with optics depending on your rifle, load and optics.

And of course, a great deal of practice to be able to shoot this accurate or better on a regular basis.

My .02