I've been using a simple 4-digit passcode on my phone. Some friends use no passcode at all, and I've felt virtuous using 4 digits. Is it necessary to use a passcode at all? Is 4 digits enough?
Certainly walking around with a phone in your pocket that has all of your life's information on it without some pass code to protect it is probably not a good idea. Certainly you'll never lose your phone but the next time you find yourself tapping your pocket and saying I wonder where I left it you'll be sorry that you didn't have a pass code to at least protect your data from the wandering eyes of strangers.
On the other hand is four digits enough? By default that's the pass code you set up on most devices but really four digits is not enough. You've seen probably news stories about trying to crack into criminals phones and if they have four digit pass codes it doesn't take very long to get the right one and in addition it's really pretty simple as you'll see if you look at videos on You Tube to find out what someone's pass code was if it's four digits just by looking at, believe me with this, the grease pattern on the phone itself.
So four digits probably not enough. I've been using it for a while and I feel even more virtuous because it takes far far longer to decode an eight digit pass code than it does a four digit. And here's another trick if you use a four digit pass code the criminal knows you're using four digits if you use more than four digits they have no idea how many digits you're using so it makes it far more difficult to decode your pass code. So yes use a pass code on your phone and most likely you're better off if you use more than four digits.