During a recent backcountry hunting trip, my cousin's boots literally fell apart! They are Red Head boots and only a few years old....according to him! He had no spares and we tried several things to do a repair job on them. We even melted pitch to try and re-glue the soles. On both boots, the soles fell off. They were only sewn on the front of each sole, rest of the sole was glued on. Finally used a combination of spare laces and duct tape. Lasted the trip!
But this is a good reason to take a spare set with you if possible.