Home security is a neccesity for all now as opposed to a optional item for a few in earlier days. While we don't have a home security system as yet, it is something that we have started to consider for the past few months, as we are often out of town. There is no official neighborhood watch in the area, although neighbors generally keep an eye out for each other. When my neighbors were away for a month, they left their apartment key with me, so their trustworthy maid could come every alternate day to clean and water the plants.
Most houses and apartments here have the regular locks in the doors and also an outside padlock, which often times people leave unlocked to make it look like someone is still inside. After a lot of consideration, wrangling, confusion and anxiety, I decided to lock our outside door when we were away for a month to the US. Everyone who went by our apartment, therefore, knew we were away for quite some time.
On the inside I do have quite a battery of locks at three different locations on the door which is quite solid in itself. Since all apartments open into a narrow hallway, there is no chain at the door, so instead we have a mini door with grills that opens inwards, that lets us check who is outside before opening the main door. Its an interesting concept that we've never had in any of our earlier apartments.