Buried in your phone’s settings, in a menu you have almost certainly never opened, is a number assigned specifically to you. It is not your phone number or your account. It is your advertising ID, and to the entire advertising and data-broker industry it is one of the most valuable things about you, because it is the single thread that ties everything you do across every app into one profile with a price on it.

Here is what it actually is, why “resetting” or “limiting” it barely helps, and why a de-Googled phone is the only version of this story where the number simply does not exist.

What it is and why it matters

Your phone has a mobile advertising ID, called the GAID on Android and the IDFA on Apple devices. It is a unique, device-level identifier handed to the apps on your phone for one purpose: to let advertisers and trackers recognize you across all of them. Without it, your weather app, your game, your shopping app, and your dating app are strangers to one another. With it, they are all reporting on the same person, you, and that linkage, the ability to stitch your behavior across dozens of apps into a single profile, is exactly the product being bought and sold.

That advertising ID is also the key that the location-data and data-broker industry uses to attach your movements and habits to you and sell them onward. When you read about companies quietly trading people’s location histories, the advertising ID is very often the identifier those histories are filed under. It is, in a real sense, your customer number in a marketplace you never agreed to join.

The part that should annoy you

On Android, the advertising ID is opt-out. It is assigned to you automatically, and you have to go digging through settings to limit it, which historically almost nobody did; by one measure only around five percent of Android users ever turned on the limit. The default is tracking, and the default is where most people stay.

Apple changed its side of this in 2021 with App Tracking Transparency, which forced apps to ask permission before using the IDFA. Given a real choice, most people declined, opt-in rates have hovered well under a third, which gutted a lot of cross-app tracking on iPhones and cost the ad industry billions. That was genuine progress.

Google’s answer was supposed to be Privacy Sandbox, a set of replacements that would phase the GAID out. But Google’s revenue depends on advertising in a way Apple’s does not, so it slow-walked the whole thing, and then, in October 2025, formally deprecated the Privacy Sandbox effort, citing low adoption. The practical result for you in 2026 is simple: on a normal Android phone, the advertising ID is still there, still on by default, and largely unchanged. The company best positioned to kill the ad ID is the one that profits from it, and it made the predictable choice.

Why resetting it isn’t enough

You can reset your advertising ID, and you can toggle “limit ad tracking” or “delete advertising ID” in settings, and you absolutely should. But understand the ceiling. Resetting the ID just issues a fresh one, and the profile-building starts over on the new number. “Limiting” is honored unevenly across the industry. And when the ID changes, trackers have fingerprinting techniques to re-link the old you to the new you anyway, using other signals your device leaks. Turning it down in settings is a real speed bump, not a wall, because the identifier still exists and the entire system is still built to use it.

The de-Googled difference

Here is the version that actually closes the door rather than leaning against it. The advertising ID is a feature of Google Play Services. A de-Googled phone does not have Google Play Services. So it does not have a GAID at all.

Not reset. Not limited. Not opted out. Nonexistent. There is no device-level advertising identifier for anyone to tie your apps together with, because the component that hands one out was never installed on the phone. That is the difference between bailing water and simply not having a hole in the boat. Opting out leaves the tracking number in place and trusts a whole industry to respect your preference. Removing Google removes the number itself, and there is nothing to respect, ignore, or work around.

The honest limit

Killing the advertising ID does not make you invisible, and it would be dishonest to pretend it does. Apps can still track what you do inside them, other identifiers and fingerprinting techniques exist, and the broader tracking machine has more than one tool. That is exactly why removing the ad ID works best alongside the rest of the approach we keep coming back to: a minimal app loadout, control over what leaves your device, no forced accounts, and opting out of the brokers already holding your data.

But the advertising ID is the single biggest cross-app linkage there is, the main highway the tracking industry drives on, and removing it entirely rather than toggling it closes that highway. Everything else is a side street by comparison.

Your advertising ID is a tracking number that was assigned to you by default, kept on by the company that profits from it, and used to sell your life stitched together across every app you use. You can reset it and limit it, and you should. But the only way to make it stop being a number at all is to use a phone that never issued one.

If you want a phone with no advertising ID to reset, because it was never there, email hello@spicycorp.com, or book a call.