Up until a few days ago I always use the bricks occasionally and sparinly. I decided to give them a try in larger amounts. So yesterday I put a whole pack in (8 bricks) and got 12hr burn with just enough relight coals. Today I got brave and put 2 full packs in. I initally loaded them at 11am tightly. They were slow to take off with the stove not reaching temp till 1pm. Then they went to 900 with damper and primary full shut. Seemed to stabilize there and as usual pipe temp was only about 300 so no worries there( always have had a cool stove pipe). Wife sent me a pic of stove at 10pm with stove top at 400 degrees and front row of 8 about half consumed and back 8 still whole. I told her not to add any fuel as I am curious to see how far these things can go. But even if they were to make 24hrs my math says too expensive for me as a soul fuel source. However if you take the true cost of traditional fuel procument into account plus all the time and effort some might say they are cheap. I guess it boils down to what your time is worth.