Your iPhone is probably still running most of the settings it shipped with. That is not a failing — Apple's defaults are reasonable — but defaults are built for everyone at once, and a few of them deserve a second look.
Think about where your phone actually sits during the day. A desk you walk away from. A café table. A shared flat. A gym bag.
What follows takes about ten minutes, costs nothing, and needs no technical knowledge. Each step explains what the setting does, so you are deciding rather than copying a list.
What a stranger can see without unlocking
Pick up a locked iPhone and you can still do a lot. Swipe down for Notification Center, up from the corner for Control Center, sideways for widgets. All of it is adjustable under Settings > Face ID & Passcode (Touch ID on older models), in the list called Allow Access When Locked.
Two entries matter most. Control Center on the lock screen lets anyone switch on Airplane Mode, which cuts the phone off the network — that matters if you ever need to find it. Reply with Message lets someone reply to an incoming message from your number without unlocking. Turn off what you do not use and keep what you rely on.
A longer passcode is the cheapest upgrade
Face ID is what you use; the passcode is what protects you. It is the fallback when Face ID fails, and it is what someone needs in order to change your Apple Account password from the phone itself.
Six digits is the default. In Settings > Face ID & Passcode > Change Passcode, tap Passcode Options and pick Custom Alphanumeric Code. The reason is shoulder surfing: a code someone reads across a table is a code they can use if the phone leaves your pocket later. Longer is harder to watch, and letters are harder still.
Turn on Stolen Device Protection
On iOS 17.3 and later, Settings > Face ID & Passcode includes Stolen Device Protection. Switch it on.
When the phone is somewhere it does not recognise as familiar, certain sensitive actions require Face ID or Touch ID with no passcode fallback, and some add a one-hour delay before they take effect. That closes a real gap: without it, someone holding both your phone and your passcode can change your Apple Account password and turn off Find My in minutes. It depends on the phone learning familiar places, so leave Significant Locations on under Location Services > System Services.
What the tracking prompt actually controls
Settings > Privacy & Security > Tracking has one master switch: Allow Apps to Request to Track. Turn it off and apps can no longer ask, and anything that already asked is treated as denied.
Be clear on the scope. This governs whether an app can use your device's advertising identifier to connect what you do inside it with what you do in other companies' apps and sites. It does not stop an app collecting data about your behaviour within itself, and it does not make you anonymous. Apple Advertising, in the same section, is a separate toggle for Apple's own personalised ads.
Location: never, once, while using, precise
Every app in Settings > Privacy & Security > Location Services has four possible answers: Never, Ask Next Time Or When I Share, While Using the App, and Always. Most apps only need While Using. Always deserves a question every time, because an app with it can note where you are when you are not thinking about the app at all.
The toggle people miss is Precise Location, inside each app's own screen. Switched off, the app gets an approximate area instead of your exact spot. Weather, news, and shopping apps work fine that way. Maps and rideshare apps genuinely need the exact version.
Do these two first
If you only have five minutes, spend them here. Set Show Previews to When Unlocked in Settings > Notifications, and confirm Find My iPhone is on, with Find My network and Send Last Location, under your name at the top of Settings. Previews decide what a stranger reads off your screen. Find My decides whether a missing phone is recoverable at all. The rest of this page is improvement; those two change the outcome.
Photos, contacts, and a report that shows you the truth
When an app asks for your photo library, iOS offers limited access, where you choose specific photos and the app never sees the rest. Revisit any app's choice in Settings > Privacy & Security > Photos. Contacts works the same way on iOS 18 and later, where you can share selected contacts instead of the whole address book.
For evidence instead of guesswork, turn on App Privacy Report in Settings > Privacy & Security. After a few days it lists which apps used your location, camera, microphone, photos, and contacts, and which domains they contacted. It is the quickest way to find the one app doing something you did not expect.
Quick answers
Does turning off tracking make me anonymous?
No. It stops apps using the advertising identifier to follow you across other companies' apps and sites. The app still sees what you do inside it, and an account or email address you handed over still identifies you. It removes one link, not all of them.
Is a warning wallpaper a security setting?
No, and it is worth saying plainly. A wallpaper that says don't touch my phone is a social signal: it discourages the casual pick-up and makes ownership obvious if the phone is handed in. It cannot stop anyone unlocking or taking the device. Your passcode, Face ID, and Find My do that.
How often should I redo this?
Once or twice a year, and after a major iOS update, since new versions sometimes add or rename settings. Also worth a pass after installing a batch of new apps, because permissions granted quickly during setup are the ones people later regret.
Will this break my apps?
Mostly no. Turning off Precise Location makes a weather app less exact, and denying the camera or microphone stops features that need them, but iOS prompts again when something genuinely requires access. Every change is reversible in the screen where you made it.
Where to get it
If you want the lock screen itself to say something, DON'T Touch Phone Wallpapers is a library of HD anti-theft and warning designs — blunt text, minimal, funny — plus general aesthetic backgrounds. Set one as your lock screen and pair it with the settings above, so the screen says one thing and the settings underneath do the rest.
Ten minutes in Settings is unglamorous work. It is also the kind that pays off on the day you need it.