[Jerry Leinsing]

Depends on builder and code.
Regardless of type, easy way to find where studs are is with rare earth magnet sandwiched in piece of tape. Flexs to move if close to a screw. Find one, then move up and down to find others, knowing that the screw may not be dead center of the stud. Got lots of money, go buy a stud finder that finds both kinds of studs. Just specify type to find.