Previous owners ruined the original (1959) solid / carved wood front door when they moved it to the garage and put a dog door in it.
It's a big one too. Big enough for my 105lb wife to get through one time when she locked herself out, and I can reach through it and grab the doorknob to get in. Basically there's no point to there even being a lock on the door to the garage anymore. Even the kind that close or lock could probably be kicked in pretty easily. The ones I've seen are just plastic.
If you want to get one and your door is nice/wood, do yourself a favor and buy a cheap door to cut the hole in so you can change it back if you move or decide it wasn't such a good idea.