Protecting your iPhone with a numeric passcode is a no-brainer, but put a little more thought into the code you select. Sadly, the most common passcodes include the ever-popular "0000," and "1234" or about as hard to crack as using "password" as your password. According to Daniel Amitay, "Formulaic passwords are never a good idea, yet 15% of all passcode sets were represented by only 10 different passcodes (out of a possible 10,000). The implication? A thief (or just a prankster) could safely try 10 different passcodes on your iPhone without initiating the data wipe. With a 15% success rate, about 1 in 7 iPhones would easily unlock--even more if the intruder knows the users’ years of birth, relationship status, etc. For a detailed look at this study, take a look at Daniel Amitay's passcode findings.