For me it really depends, on familiar trails, or well marked parked trails, I won't even look. On ones I've done multiple times as well as side approaches I won't even take one.

For off trail stuff on the other hand, I do look. often not so much because I can't get where I'm going without one, but looking at one when off trail in mountains really helps you find the better ways to get there.

On flatter ground it's pretty much useless - my favorite stuff there is actually air photos - so I know where the cutlines and the forest cover types are. - but again, only if I'm not familiar with the area already.