The locks on your home are, in some ways, like the password on your computer, phone or personal internet sites. They protect vital and important information, belongings—and sometimes, your life. Just like you change your passwords to protect your identity and information, you should change your locks, as well.

Obviously, you don’t need to change them as often. There are, however, certain instances that should force the issue.

If you move
If you move into a new house, one of the first things you should do is change the locks. You don’t know how many people had access to the dwelling while the former owner or occupant lived there. Besides, changing the locks can be a personally satisfying thing: it’s your key to your home. That’s also true if you have a roommate that moves out. If necessary, call your landlord and request it.

If someone breaks in
If someone breaks into your home, chances are your locks didn’t work well, anyway. If the intruder came in through a broken window or other form of egress, it’s still possible that he or she may have stolen a key and could return at another time.

If they’re old, stiff or simply don’t work
Door locks fail over time, just like any other mechanism. Time and the elements and regular use will make your locks more difficult to turn. Make sure to replace your locks if you notice this happening—don’t wait for the lock to get so stiff the key bends or breaks off inside or the lock stops working, altogether. Often, older locks can be re-keyed instead of replaced, but it’s safer and better in the long run just to swap out the set.

If you lose your keys
It doesn’t matter how long they are out of your possession or if some kind-hearted soul returns them to you. That same kind-hearted soul may have copied them before he turned them into the lost and found and may be waiting for you to claim them so he can follow you home. Call a locksmith on the way.

If you get divorced
Yes, we know you once entrusted your life and love to your significant other. That doesn’t mean you have to entrust your home to them if things go south. It may sound harsh, but if you are forced to separate from your spouse, make sure you get new locks.

If you give your keys to your children

When your kids get older, it’s easier to give them their own key so they can let themselves into your house than it is to arrange after-school child care. Children, however, are notorious for losing things. If they’re of that age, change your locks regularly.

If you leave a key for a repairman

If you have a neighborhood handyman or even a service person from a reputable firm do some work while you’re away, you should consider changing your locks. It’d be nice to be able to trust such folks, but we no longer live in that kind of world.

To upgrade
If you still only have a regular knob lock, you should consider upgrading to a handle/deadbolt combination—at the very least. It’s true that if someone wants to break into your house he or she will most likely find a way, but a good solid lock set will discourage most attempts.