Do I really need a sliding hitch?

I think it will be hard to tell until you actually have the whole combo hooked up and encounter a tight turn situation and then too late and expensive to change hitches. I have a shortbox(6 ft.6 in.) and I definitely need the slider to get backed into my driveway plus I use it on the average about once a trip. Sometimes just for precaution. And yet I never had one on a slightly older truck that should have had the same measurements. Can't figure that one out.