How much time does one usually spend there?

I would plan on spending about an hour. Gives you time to read all the plaques throughout the trail.

We spent a couple hours there as there is a nice gift shop and a small Museum very interesting enjoyed the Petrified Forest

We spend approximately an hour when we go.

One and a half..

2 hours

I would give it 2 hours

1 1/2 hours

We spent a couple of hours there. Half on the trail and half in the little museum and gift shop.

30 min