I always cut grapes, hot dogs, etc. Anything with a somewhat tough outer skin that is round or hard to chew (baby carrots get slivered too.)
However, knowing what to do is important as well. I have had children choke on bananas, grapes, pizza cheese, a hard candy stolen from someone else's restaurant table, a pretzel bite, a chunk of steak, a cheese cube, etc, etc...
And the kids range in age from a 2 yo to a 12 yo. It can happen anytime to anyone.
We do the best we can, and know how to recognize choking, and what to do if it happens.