Smokers and BBQ
Just take a 2 tine long kitchen fork and poke it into the brisket in various places. If it slides in AND it slides out with no tension (EVERYWHERE you poke) the brisket is done. If it sticks when pulling out in any part of the brisket, it's not done...no matter how long it's been on the pit...no matter what the internal temp. We've had to take them as high as 210+ internal. Not often with Choice, but it's not a rarity, either.
Another thing about time...you'll be best served if you leave your brisket on the counter for 30-45 minutes in order that the juices have time to re-distribute back from the surface of the meat. You do not want to cut into that brisket and have juices flowing everywhere. That's one of the causes of dry brisket that many folks tend to overlook. Rest that sucker before you cut into it.