I like using the Simple Passcode option on my iPhone, but I've always been kind of bugged by the idea that there are only 10,000 possible passwords under that scheme. Since it's always 4 numbers, lots of people tend to use a month/day combination which makes guessing a fairly easy task for many people. Is your first digit 0 or 1? Do your 3rd and 4th digits add up to no more than 31? Is your combination your birth year? Last 4 of your phone number?
If you would like a longer simpler password, here's a cool and easy trick I just learned:
Open Settings on your iDevice and go to "Touch ID & Passcode."
Turn off "Simple Passcode"
Next, change your passcode to something longer, using all numbers.
Enjoy your new improved security!
Look what happens when you get to the lock screen now! Instead of needing to enter your long password with the keyboard (really kind of a drag) you just punch it in on the keypad (not too shabby!) The only difference between this and the simple passcode option is that you need to tap the "OK" after entering your code.
OK, I lied. The only difference is you have to tap OK, and your password is now more than 111,000% harder to crack! (Assuming you have used 7 digits.) You've gone from 10,000 combinations to 11,111,110. Add one more digit and you've increased the number of combinations to over 100,000 which is more than a One Million Percent increase!
I really like the idea that the length of my passcode is no longer known. While I'd never recommend a 1, 2 or 3 character code, a would be thief/hacker would have to try all of them in order to rule them out. They also need to try all the 5, 6, 7 and so on combos, thereby increasing the amount of time it will take to unlock your phone.
Yes, you may have set your phone to erase all data after 10 failed passcode attempts, so perhaps you're not too worried. Then again, you may have a kid or a wise guy friend who just loves wiping out all your data every so often. Me? I'd rather not have to restore from a backup. And if you're one of those people who says "Back… what?" or doesn't know how to restore from a backup or one of those who knows how long it takes to restore from a backup, maybe you would like to make your password a little bit longer and less obvious than a sentimental date.