Locks have a fascinating history. As a kid I was on a mailing list for a locksmith school. It’s a good trade and I sort of wish I’d followed up on it. At the time, I was afraid of being under suspicion all the time. When a crime is committed, call the locksmith. Once you get involved in security, you are under surveillance.
A friend of mine has locked herself out of her apartment twice in the last six months and the locksmith made a fortune. Something like $450 a pop for a half hour of work. (Not endorsing this locksmith service. I just saw the sticker on my steps as is and took a photo.)