Obviously, it's not necessary to use any of the code mentioned above. Even myself do not use all these strategies in any code I am writing. But it is quite possible that using some of these strategies can keep you out of some big trouble. No, having your scripts exploited is not a certain thing, but it is a possibility you must consider. And the above examples are, by no means, difficult to implement.  Please do not read this and believe it is a complete guide for securing your PHP applications, it is just a small piece of a larger puzzle.