On my pellet grill 10 hours. Boston Butt. Took longer than I thought it would. Doing my first cook today on the vertical and so far so good. I am 7 hours in so far, prob 3 more hours so this will prob be a 10 hour cook as well. I just don't feel safe doing an overnight cook without checking on it from time to time but this vertical smoker holds temps better than the grill. Lots of temp swings on the grill, not on this one. The vertical could very well be set it and forget it.