I bought a prehung door and had some questions about it. The Jambs are 4.5″ wide. The Studs are normal 2x4s. The hinge is mounted so close to the edge that the screws will not hit the stud, so all the hinges screw into is a piece of 5/8″ wood. That doesn’t seem strong enough to hold a door for very long. I would have liked to use some 3″ screws through the hinges into the stud. Does this seem correct or did I get a bad door? It seems when I hang the drywall the hinge screws will run into the side of the drywall.

I always install drywall before the door, the drywall will be trimmed to the rough opening, and any gap will be covered by the door trim. You can replace a hinge screw with a longer one, if you feel it necessary, but I have never had an issue with hanging interior doors with 10 D finishing nails. I always use longer screws when doing an exterior door.

If it is a hollow core door, it’s fine. The center (back) screw should be far enough back to put a longer screw in the henge to go into the framing.