I lost my iPhone over Thanksgiving weekend. I eventually found it in my wife's car, which I never drive but did on Thanksgiving ever so briefly when we were juggling cars in the driveway with my parents visiting for the holiday.
Long story short: it was a very disconcerting feeling and one I'd rather not experience again soon. Because I'm lazy (one word for it), I didn't have a passcode set up on my iPhone, which meant that anyone that may have come across my phone would have had unfettered access to my emails, texts, photos and other information. Thankfully, I set up Find my iPhone and was able to use that security feature to lock my phone remotely.
Even though my story ended happily with my iPhone safely returned after never actually having left my yard, I learned a few lessons during the process of losing my iPhone for a few days.
1. Use a passcode
I now use a passcode. The standard passcode for iOS 9 is a six-digit passcode, though you can increase the strength of the passcode by choosing an alphanumeric passcode or a numeric passcode longer than six digits. You can also move in the opposite direction and choose a four-digit passcode, which was the default option prior to iOS 9. (Even if you set up Touch ID to use your fingerprint to unlock your iPhone, you'll still need a passcode for times when your finger is sweaty or wet or otherwise can't be read by your iPhone's fingerprint scanner.)
To turn on a passcode, head to Settings > Touch ID & Passcode. Tap Turn Passcode On and enter a six-digit code. To downgrade to a more convenient but less secure four-digit passcode or a stronger custom passcode, tap Change Passcode and then tap Passcode Options.
2. Disable lock screen options
Even if you have a rock-solid passcode, a nefarious individual can still get into your phone via the lock screen. In her efforts to be helpful, Siri can share too much information from the lock screen, freely displaying personal information to whomever finds your lost phone. If this thought scares you, then it's best to disable Siri from the lock screen.
To do so, head to back to Settings > Touch ID & Passcode and toggle the slider switch to off for Siri in the Allow Access When Locked list. You may also want to disable Wallet, which will force you to unlock your phone before paying via Apple Pay. Also, the Today and Notifications view options will prevent those screens appearing from the Notification Center when your phone is locked. And the Reply with Message prevents someone from replying to a text on your phone without first unlocking it.
3. Make your iPhone lock sooner
If you leave your iPhone behind in a restaurant, bus or another public place, someone could act quickly and get into your phone before your passcode is required. You can set your passcode to be required after a certain amount of time has passed since you last unlocked your phone so that you aren't constantly being asked to punch in your passcode each time you attempt to get into your phone. You can set it up to four hours, which is on the convenient end of the convenience vs. security spectrum.
This setting can be found on the Touch ID & Passcode page of Settings. The most secure option is to set Require Passcode to Immediately, which will require you or anyone who picks up your phone to enter your passcode no matter how long ago your last unlocked your phone.
4. Disable Control Center on lock screen
Another way hackers can get into your iPhone or at least buy some time to find a way to circumvent your passcode is to enable Airplane mode via Control Center from the lock screen. Once it's in Airplane mode, you won't be able to track it via Find my iPhone.
To prevent Control Center from being accessible from the lock screen, head to Settings > Control Center and toggle the slider off for Access on Lock Screen.
5. Turn on Find My iPhone
Even if you have ignored the first four steps here, I implore you to enable Find My iPhone. It doesn't add any inconvenience in the day-to-day operation of your iPhone and is easy to set up. With it enabled, you can track your lost device from another iOS device or your computer, seeing where your iPhone is on a map. You can also play sound on your lost phone to aid your search efforts (which turns out isn't helpful when your phone is locked in a car in your driveway). And if you really aren't having any luck with locating your iPhone, Find My iPhone lets you lock your iPhone and also remotely erase its data.
To turn on Find My iPhone, go to Settings > iCloud. Tap on Find My iPhone and toggle the switch on for Find My iPhone.
6. Set up two-step verification
For this last tip, I'll turn it over to Jason Cipriani, who previously wrote about how to enable set up two-step verification for your Apple ID. Two-step verification protects the data you have stored with Apple, including photos and files in iCloud and payment information for iTunes. With two-step verification enabled, someone would need another of your devices to get into your account even if they had managed to get a hold of your password.