My power was out from 5am thru basically all of yesterday, so I'm late here.
Cook time depends on the amount/thickness of meat.
A full packer brisket is usually like 10-12lbs and can take 1-1.5 hrs per lb of meat.
I've done full packer briskets where I start them around midnight before when I want to serve it and cook it for 16-18 hours.
What I cooked and posted was not a full packer brisket, it was only a cut (point I think, a brisket has a point cut and a flat cut)
It was only about 5.5lbs and my butcher had cut it away from the full packer to sell separately.
And as
@Burque said, when the meat stalls, wrap it up tight in the heavy duty foil or your cook time could balloon by 6-8 hours.
Also, if you've had it on your smoker up to the stall, you can wrap it, put it on a baking sheet, and finish it in the oven at 225-250.
Either way, if you are cooking a big hunk of meat (think pork butt, brisket, etc) you'll need to wrap it when it stalls or build in an extra 4-6 hours to get thru the stall.