Today we attended an emergency locksmith job in Ivanhoe which provides a good example of why deadlocks are often the difference between a break-in and keeping your home secure.
Deadlocks provide extra protection because they are stronger than a simple lock set. However, you need to make sure you go for a quality deadlock, with hardened steel bolts that are at least 2cm long.
A single cyclinder deadlock should be sufficient but if you have a glass panel in your external door then you might want to consider a double cyclinder deadlock. This is because even with a deadlock an intruder can break the glass and open a single cylinder deadlock from the inside.
Double cyclinder deadlocks require a key to open them from either side (internally or externally). You will need to consider the convenience of this. Also, it is illegal to put a double cylinder deadlock on a fire door.
So in this case, if a good quality deadlock had been fitted this would not have happened.
For more information and advice on what kind of doors to use for external purposes and to make your locks as secure as possible, check out Doityourself.com