Key Takeaways
Why Default Settings Work Against You
When you set up a new phone, download an app, or plug in a smart speaker, the device is almost never configured with your privacy in mind. Manufacturers and app developers set permissive defaults — collecting diagnostic data, enabling ad tracking, and sharing location history — because that data has value to them. Most users never change these settings, often because they don't know they exist.
That's not a character flaw; privacy settings menus are frequently buried and use vague language. But the settings below are worth finding. Each one is available on widely used platforms, takes only a few minutes to change, and has a concrete effect on how much data leaves your device. For a fuller picture of the broader landscape, see The Complete Guide to Protecting Your Privacy Online.
Ad Tracking Identifier (Limit Ad Tracking)
Every smartphone assigns your device an advertising identifier — a code that allows apps and ad networks to build a profile of your interests across multiple apps. On iOS, this is the IDFA (Identifier for Advertisers); on Android, it's the Google Advertising ID. Both platforms now let you opt out of apps using this identifier, and you can reset it to break existing profiles.
On iOS, go to Settings > Privacy & Security > Tracking and turn off Allow Apps to Request to Track. On Android, navigate to Settings > Privacy > Ads and select Delete advertising ID. This doesn't eliminate all ads, but it prevents cross-app behavioral targeting based on a persistent identifier tied to your device.
Resetting your ad ID breaks the profile ad networks have already built from your behavior.
Location History and Background Location Access
Location data is among the most sensitive categories of personal information because it can reveal where you live, work, worship, receive medical care, and spend time. Many apps request location access during setup and continue tracking it in the background long after you've stopped actively using them.
On both iOS and Android, you can set location access per app to While Using the App instead of Always, or deny it entirely for apps that don't need it. Separately, platforms maintain their own location history logs. On Google accounts, visit myaccount.google.com > Data & Privacy > Location History to review and pause this feature. Turning off background location for apps that have no legitimate need for it is one of the highest-value changes you can make.
Background location access lets apps track your movements even when you're not using them.
Diagnostic and Usage Data Sharing
By default, most operating systems share diagnostic reports, crash logs, and usage statistics with the device manufacturer or platform developer. While this data is described as anonymized, research has consistently shown that detailed behavioral data can be re-identified more easily than most people expect.
On iOS, go to Settings > Privacy & Security > Analytics & Improvements and toggle off Share iPhone Analytics. On Android (varies by manufacturer), look in Settings > Privacy or Settings > About Phone for usage and diagnostics options. On Windows, search for Diagnostic data settings and set it to Required only rather than Optional. This is a low-friction change with a meaningful reduction in routine data transmission.
Diagnostic data described as anonymized can often be re-identified through behavioral patterns.
Personalized Ads in First-Party Platforms
Beyond third-party ad tracking, the major platforms — including search engines, social networks, and streaming services — use your activity on their own services to serve targeted ads. This setting is separate from the device-level ad identifier and requires opting out within each platform's own account settings.
Look for options labeled Ad personalization, Personalized ads, or Interest-based advertising in each service's account or privacy settings. Turning this off doesn't mean you'll see fewer ads — it means the ads will be less precisely targeted to your browsing and search history within that platform. It also limits how thoroughly your on-platform behavior is profiled and retained for commercial purposes.
First-party ad personalization is a separate opt-out from device-level tracking — both matter.
Smart Device Microphone and Camera Access at the OS Level
Smart TVs, voice assistants, and connected home devices frequently request microphone and camera permissions that persist well beyond any obvious functional need. Even when a device isn't actively being used, certain features — like wake-word detection — keep the microphone in a listening state by design.
Review microphone and camera permissions at the OS level on your phone (under Settings > Privacy on both iOS and Android), and also within the companion apps for any smart home devices you use. For voice assistants, most platforms offer settings to delete your voice history and limit future recording retention. If you're evaluating whether a smart device is worth adding to your home network at all, the questions to ask before buying a smart home device is a useful starting point.
Voice assistants stay in a listening state by design — reviewing recording history settings is worthwhile.
App-Specific Privacy Controls Within the App
OS-level permissions are only one layer. Many apps have their own internal privacy settings that control data collection independent of what the operating system allows. These are commonly found under the app's Settings or Account menu and may include options to limit data sharing with third-party partners, opt out of research panels, or restrict targeted content recommendations.
Social media platforms and messaging apps are particularly worth checking here. Look for sections labeled Privacy, Data, or Ad preferences within the app itself. These controls can include whether your activity is used to improve the platform's algorithms, whether your data is shared with advertisers, and how long activity logs are retained. App Store privacy labels can help you identify which apps collect the most data before you even install them.
OS permissions and in-app privacy settings are separate layers — both require attention.
Make This a Habit, Not a One-Time Fix
Privacy settings aren't a set-it-and-forget-it fix. Operating system updates sometimes reset toggles you've changed, and apps can add new data-collection features with little notice. A quick check of your settings every few months — particularly after a major OS update — helps you stay ahead of new defaults.
These adjustments also work better in combination. Disabling ad tracking while still granting every app access to your contacts and microphone leaves significant gaps. Consider pairing what you've learned here with a broader audit of app permissions worth reconsidering, and be mindful of the risks covered in our piece on common online privacy myths. Small, stacked changes produce the most durable results.
Check Settings After Every Major Update
Operating system updates — both on mobile and desktop — can reset privacy toggles to their defaults without notifying you. After any significant OS update, spend five minutes reviewing your key privacy settings, particularly location access, ad tracking, and diagnostic sharing. It's also worth checking whether any newly installed apps have been quietly granted permissions during the update process.