It's been shown time and again that quality deadbolts, properly installed, are still the greatest break-in deterrents for doors.
1) The bolts themselves of today's deadbolts extend a full 1" when locked. That means a door would have to be gapped by 1" when pried from a door frame. A lockset typically has the bolt extending 1/2 - 5/8"... easier to gap when prying.
2) The bolt also 'deadlocks' when extended, meaning you cannot work the bolt back into the door edge by nudging it back a little at a time with a knife blade or screwdriver tip. Also, one cannot shim the door bolt with a credit card or folded piece of paper.
3) On quality deadbolts, you'll find a hardened steel rod integrated in the bolt to protect against sawing. Hacksaws take a very long time to cut through hardened steel. It also tends to dull the blades quickly.
4) The strike plate used with a deadbolt is typically attached to the door jamb with 3" screws which penetrate and anchor into the stronger wood studding behind the softwood jambs. This really helps to prevent or dramatically slow down a kick-in attack.

There are two main types of modern deadbolts: The single cylinder and double cylinder.

Single cylinder deadbolts are the most common and use a key on the outside of the door and a turn-piece on the inside of the door for locking and unlocking.

Double cylinder deadbolts use a key on both sides of the door. They are usually found on doors with glass panes in them. This prevents a burglar from simply breaking the glass and reaching in to unlock a single cylinder deadbolt by just turning the turn-piece. WARNING! Double cylinder deadbolts are dangerous and illegal use in some municipalities. The reason is that occupants can be locked and trapped in their own buildings by not being able to unlock the deadbolt fast enough to leave in a hurry. People have died that way. If you have a double cylinder deadbolt in your door(s), please always have a key in the inside cylinder so you can quickly turn to unlock without fumbling for a key in emergencies. It may seem like having a key in the lock defeats the purpose of a double cylinder deadbolt, but you would only do that while in the building. When home or in the business, you stand a lower risk of physical break-in than when away. When the building is not occupied, remove the key from the inside, lock the door from the outside and enjoy greater peace of mind.

Always buy deadbolts of reputable manufacturers. Brand X locks from certain asian countries are not a great value if the quality construction is below par. You DO get what you pay for.

Quality deadbolts really do protect against kicking, prying, sawing and shimming. We'll address the other form of attack on deadbolts, lock picking, in a future installment. We'll also address keyless locks.

We have double-cylinder deadbolts on most of the doors of our house. We weighed the chances of our having a fire versus the chances of our young son unlocking a door and running into the street, as he has previously climbed out a window with me in a nearby room, totally unawares.

I don't really like it, but feel that it is necessary until he learns more self-control.

Suggestions, Dottie:
1) Tap a small nail into the door jamb high enough that the child can't reach it, then hang the key there. That way you'll find the key quickly, yet keep him from escaping.
2) Partially insert the key into the cylinder so it won't turn. Downside, the child may take the key and lose it.
3) Install a slide bolt above reach and use that simple lock to keep the door secured while home.

All in the name of life safety.

If his really smart he'll probably figure out how to pull a chair over and climb up and grab the key. :)

pk

He's eight!! And very skilled at climbing, as when he first climbed out a window and climbed back in wearing only a diaper, pulled himself up into a window that was almost shoulder high, scratching his whole front. But his emotional age is about 4. . .

Dottie how frightening! Thank our good Lord he came back in and didn't keep exploring.

bump

Amelia--

What happened was that the doorbell rang, and there were three women outside. At first I thought they were JW's, but they didn't have any papers. One of them asked if I knew my little boy was outside. I said, "No, he's right here."

He saw the ladies coming toward the house and climbed back in the window in a hurry, and was standing by me when I opened the door. I had come from one end of the house, and he had come from the other!!