I think it is fair to say that, for all sorts of reasons, the Tutor isn't being worked nearly as hard as the Bulldog was. Nevertheless, the Dog was a solid piece of engineering and could cope with a whole spectrum of the usual abuse, and more, associated with ab-initio training. Tutor and Firefly are 'soft' by comparison and will never last as long, given the same sort of use. Nowhere near as long.