How to set up a hand-me-down phone for a child
Short answer
Back up and factory reset the phone first, then set it up from scratch signed in to your child's own Google account rather than adding their account alongside yours. Do the reset with the phone above 70% charge and connected to wifi, and know the Google account password on it — if you changed that password recently, Google advises waiting 24 hours before resetting. Then add Family Link, a Play Store PIN, and decide where the phone sleeps.
The cheapest good first phone is usually one the family already owns. A three-year-old Android that a parent has stopped using does everything a ten-year-old needs, and it arrives without the ceremony of a new box, which is its own quiet advantage.
The catch is that a handed-down phone carries its previous life with it. Done carelessly you get a device still signed into a parent’s account, with a parent’s photos, a parent’s saved passwords and a browser full of a parent’s history. Done properly it takes an evening.
Wipe it first, always
Adding a child’s account to a phone that still has yours on it is the mistake that causes the most trouble later, because the two accounts share the device and the supervision never quite behaves.
Google’s own guidance before a factory reset is specific:
Know the Google account username and password currently on the phone. Confirm the password works by signing in somewhere else first. If you changed that password recently, wait 24 hours before resetting — this is the step people skip and then find themselves locked out of a phone they own, because the protection that stops a stolen handset being wiped and resold cannot tell the difference between a thief and you.
Back up anything you want to keep. A factory reset erases the phone, and all apps and their data are uninstalled with it.
Google asks for at least 70% battery and a wifi or mobile connection, because the phone needs to be online to sign in once it restarts.
The reset itself lives in the Settings app on most phones, though the exact path moves around between manufacturers — Google points people to their device maker’s support site for that reason rather than publishing one path that would be wrong for half of Android.
Then set it up as theirs
Sign in with a child account, not yours
Create the account through Family Link if they do not have one. What you are avoiding is a phone that technically belongs to you with a child using it, which is a worse arrangement than it sounds — it makes every rule ambiguous.
Add supervision before you hand it over
Install Family Link, set the daily limit, set bedtime, and set per-app limits. Doing this before the handover matters more than the settings you choose, because a phone that arrives with rules feels different from a phone that has rules imposed on it a fortnight later.
Set a Play Store PIN
In the Play app, tap the profile icon, then Settings → Family → Content restrictions → Go to parental controls → Set up a parental controls PIN. Use a PIN they have not seen you type. Without it the filters can be switched off by the person they exist for.
Check what survived
Open the app drawer and look at what is actually installed. A wiped phone restores apps from whichever account signs in, so a child account that has existed on a family tablet may pull down a surprising amount.
Two things worth deciding before you hand it over
Where it sleeps. Decide this once, in advance, and preferably somewhere that is not the bedroom. It prevents more trouble than any filter, and introducing it later is almost impossible without it reading as a punishment.
What unlocks next. An old phone can do everything, so the restrictions are entirely a matter of what you switch on. Say out loud what comes next and what has to happen first. A phone with a direction is a different object from a phone with a fence around it.
Why the old phone is often the better option
A dedicated child’s handset solves the first-phone problem by removing the capability. That works well at nine and becomes the reason for another purchase at thirteen, because the restrictions that made it right are the ones the child grows into resenting.
Hardware you already own does not have that shape. The same device can relax as the child does, which means the upgrade conversation is about permissions rather than about buying something. It is also free, and the money is better spent on the bike they are saving for.