Full Briscket-

Personally, I trim the fat down to about 1/8 to 1/4 on the flat portion. For the point, I remove the "corn" or "kernel" along the side and then I remove all the big gnarly hunks that don't render off. I score the fat on the flat side, season, and cook fat side up till 195 internal on the flat.. Rmove, foil, and rest for at least one hour. I usually cook briskets at 16 or more pounds..

This forum is for Grilling so if you are using a RF smoker, post up brisky threads in the beef section just below this one...

If I am cooking Brisket at home, I'll leave all the fat on / in unless it looks slimy / snotty.  It is way easier to trim the fat off the brisket when it is cooked and more fat in the cooking process isn't going to hurt.

At comps, I will trim the thick vein of fat between the flat and the point and shave off the fat to a thickness of 1/4" on the flat prior to cooking.  This leaves some fat to render through the meat during the cook but I rely on the injection and cooking process to keep the flavor and moistness in the meats at a comp.  After it is sliced, I will remove the remaining fat from the bottom of the slices.

Normally I trim very liitle fat off. Maybe the really thick hard fat cap but then I only trim it down a little bit maybe a half an inch. I like to smoke the brisket with all the fat so it keeps the meat juicy and after all I'm a firm believer of:  Fat=Flavor After all what is Marbling????

What they all said. Trim it to approx 1/4" thick, don't worry if you expose a little meat here and there, trim any large veins/chunks of fat as best you can. Cut a criss-cross pattern in the fat, just down to the meat, then make sure to really get your rub down in cuts.