And so it may well happen that you will have to replace the door frame over time during the long life of the entrance door.
Don't give the heat a chance to escape
With old frames, you will often have to deal with the problem of insufficient adhesion of the door. In this way, you will lose part of the thermal insulation properties, and the sound insulation of outdoor noises will also be in a bad position. The door will stick to the new door frames 100% and the heat will no longer escape through them.