What's the average burn time for the 22" WSM?

I get between 7-9 hrs on mine using a 12lb bag of K Comp.
Might go longer, but I haven't had the need.

I got about 12 hours at 215*-235* for a couple of pork butts with a not-so-full load of standard (blue bag) Kingsford and a few large chunks of apple and mesquite. I used the Minion method to start it and never added any extra. It still had coals left when I took the pork off, and I had the lid off a couple of times during the cook for burgers and a fatty.

I probably could have loaded it up more, but it holds so much more than the old 18" did that I figured it wasn't a problem (and it wasn't)...