If you have an older front door that needs to be replaced, you can replace it without removing the jamb (frame) if the jamb is still ‘square’ and is not damaged. You must make sure you are getting the same size door, of course, or it won’t fit.
You don’t need special tools. It is easy to knock out the hinge pieces with a hammer and a chisel or screwdriver.
Remove the old door from the old frame using a cordless screwdriver or drill. Be sure to leave the hinges on the door. Place the door with the exterior side down on a couple of sawhorses and remove the doorknob.
Place the new door on top of the old door with the exterior side down and make sure the doors are flush with each other around the perimeter of the door.
Use a pencil to outline the stencil and trace the three hinges from the side of the old door to the new door. Now you can unscrew and remove the old hinges from the door. You use them again on the new door.
Remove both doors from the sawhorses. Stand the new door on it’s side with the hinge side facing up. Clamp it to one of the sawhorses and place the hinges on the door as if they were already installed on the door using the pencil lines to align them. Complete the tracing around the hinge plates.
Cut around your pencil stencil with a utility knife or box cutter. Hold the chisel with the bevel side up and rock the chisel back and forth across the grain inside the hinge stenciling to remove all of the wood to about 18 inches deep. Tap on the back of the chisel if you need to, to get it to cut.
Insert the hinge plate into the hinge cut-outs. If they don’t fit flat, or won’t fit into the tracings, continue cutting and shaving the cutouts until the hinge plates fit snug and flush into the hinge cutouts, called mortises.
Screw the hinges to the door using the old screws and the cordless screw gun. Hold the new door in place on the frame. Tap the hinge plates back into the jambs. Use the screw gun to screw the hinges onto the jambs.
Put the doorknob on.
Kick back with a cold one and celebrate you handyman skills!