I see the same situation almost every day: someone brings in their phone, completely locked out because they factory reset without removing their Google account first. The look on their face when I tell them it'll cost money to unlock? Not fun. Here's how to avoid becoming that person.
1. Know Your Google Login (For Real)
I can't tell you how many people come in and say "I think it's this email..." or "My password is something with my dog's name." That doesn't work with FRP. You need the EXACT email and EXACT password.
What I do personally: I keep a small notebook at home with all my important logins. Yeah, it's old school, but it works. Password managers are great too, but make sure you actually remember the master password.
2. Remove Your Account BEFORE You Reset
This is the big one. If you're planning to factory reset your phone for any reason, go to Settings → Accounts → Google and remove it first. Takes 10 seconds and saves you hours of frustration.
I've seen people skip this step because they're in a hurry or someone on YouTube told them to "just reset it." Don't be that person.
3. Selling Your Phone? Do This First
If you're selling or giving away your phone, remove your account while you're still holding it. I've had people come back to me weeks later saying "the buyer wants their money back because the phone is locked."
Trust me—remove the account, THEN reset, THEN hand it over. In that order.
4. Buying Used? Check for FRP First
Before you pay for a used phone, turn it on and go through the setup. If it asks for a Google account that isn't yours, walk away. I don't care how good the deal is.
A "great deal" on a FRP-locked phone is just an expensive paperweight.
5. Write Down Your IMEI
Dial *#06# and write down that number somewhere. If you ever need professional help unlocking your phone, we'll need it. Also useful if your phone gets stolen.
Follow these simple steps and you'll never have to deal with FRP lock issues. It's that easy.