When I was in college everyone got locked out of their dorm room. The first time you called Public Safety to unlock your door it was free. Then they started charging you $10 or $20 bucks. I resolved to never let this happen. So I designed a system to avoid getting locked out. It works flawlessly. In the decade I’ve been running this system, I have never once gotten locked out of my house. Even better, it is so bulletproof that I never have to worry about getting locked out of my house.

The system has 3 parts.

1. Get a Huge Carabiner

First, you need a huge carabiner. Not one of those dainty ones that everyone else puts their keys on. A huge one. The kind that you could use to escape from a burning building by ziplining down a convenient cable that runs from the roof you’re on to a non-burning building nearby. In other words, an actual rock-climbing carabiner. I use the DMM Aero (around $10) and love it. It’s lasted me over 5 years with 0 problems.

When you enter your home, clip this carabiner to your inside door handle. Now, each time you leave, you can’t help but notice your keys, because they’re on the handle that you turn to leave. This solves the problem of forgetting your keys inside.

2. Use Deadbolt Only

Next, you only use the deadbolt on your door and NEVER EVER use the little auto-lock on your door handle. The handle lock adds ZERO security beyond the deadbolt. If someone is willing to break through your deadbolt, your handle lock is not going to stop them. All it does is make it likely that you lock yourself out if you do happen to exit your house without taking your keys.

If you always take your keys (thanks to the carabiner technique) the handle lock isn’t a problem, but the operating principle here is Defense in Depth—this system needs to function even if you screw up one of the steps.

3. Get a Lockbox

Finally, get a lockbox, place it on the outside handle of your door, and fill it with an extra set of keys. I use this one from Master Lock (around $20). Memorize the password. If you don’t trust your memory, also store the passcode securely in a password manager on your phone.


Now, if you lose your keys while you’re out, you just enter the code on your lockbox and you can get back in. A side benefit is that you can let someone into your house while you’re away.

This system eliminates the following failure modes:

  1. You forget your keys and get locked out when someone else locks the door.
  2. You forget your keys and get locked out when the handle locks itself.
  3. You lose your keys while out and can’t get back in.

It only requires two purchases totaling around $30 (as of writing):

  1. Huge (and stylish) carabiner
  2. Door lockbox

Think of the $30 outlay as an insurance premium that you only have to pay once and it protects you forever. How much does it cost in time, money, and stress if you get locked out?