Having just replaced all nine hollow-core interior doors with nice solid core doors in the house, I can testify that if you have less than 1/2" of shimming in the door, you are lucky. Every single one was at least that, and two were an inch. I used 3" screws to secure the jamb to the framing, first nail to fit, then add the screws for security, at least that's what I did. You can use the new plastic shims, they won't split like the wooden shims do, made the install a bit easier.
Had a good time finding 3" oil-rubbed bronze screws, though. Next time I'll just paint the heads.
Soon as the doors are all painted, the new alarm system goes up. Uses cellular phone links so cutting the phone wire won't silence it.
I've got dead bolts on all exterior doors, of course, but added a deadbolt to the door between garage and laundry room, then another between laundry room and main interior space. So it's going to take some time to get through all that.