hah, yes, I'm that other owner 
experienced and all
for starters, if you burn the frankincense, first turn off your smoke detector or all hell will break loose - forgot it twice and the second time, my neighbours were banging on my door in panic (I must say I overdid it a bit, the smoke and such)
the charcoal burns a long time alright, but you have to encourage it a bit every now and then; if you see it is going down, best to put aside the frankincense, take the charcoal tablet with the tweezers and gently blow on it until you see it starts glowing again.
I also break it in two pieces, half of it is enough for fogging the life out of your living room 
