One of the first things we had to do when we moved into the house was childproof the exterior doors. In the apartment we were able to use knob covers long enough that the boys pretty much gave up trying to open the doors, that is until they came around and changed all the knobs to levers, then it was on! The boys opened & closed the door all the time. They also opened the door & ran outside quite frequently, most often in the nude! The apartment was small enough though that I could hear if the door opened from pretty much any room. The house is a whole different story though in size & number of doors for little escapees to get out.
So my bonus dad hooked us up with these cool, discreet little locks for the front door & the door that leads out to the garage.
The house came equipped with a handy little aluminum pole that locked the sliding door in place. It took the boys exactly 3 minutes to break it & 3 days to completely disassemble it :-/ So we had to find another solution for that door too. Some similar little flippy hinged lock did the trick there as well & now everyone is secured in the house & I shouldn't have to worry about any streakers running down the street :)