I’ve always put a damper in the stovepipe above the stove. Dunno why, we always had one growing up I guess. I find it does slow the burn down and like Henrysforest says, you may notice some extra creosote, the damper is gonna slow the draft and run a cooler chimney . All my chimneys and stovepipe run straight up, no 90’s, so I always have had strong draft that is nice to slow down for the night at least... each set up is gonna be different!