"Not your keys, not your coins." It's the oldest piece of advice in crypto, repeated so often it's become background noise. And people still ignore it — usually right up until the day an exchange freezes withdrawals and they learn the lesson the expensive way.
Here's what the phrase actually means. When your crypto sits on an exchange, you don't truly hold it. The exchange does. What you have is an IOU — a promise that they'll give it to you when you ask. Most of the time, that promise is honored. But "most of the time" is doing a lot of heavy lifting in that sentence.
History is littered with exchanges that collapsed, got hacked, or simply locked users out, taking everyone's "balances" with them. In every case, the people who held their own keys — in a self-custody wallet where only they control access — kept their funds. The people who trusted the exchange didn't.
Self-custody isn't complicated anymore. A reputable wallet, your recovery phrase written down and stored offline, and the discipline to never share it. That's most of the battle.
The convenience of exchanges is real, and there's nothing wrong with using them to trade. But for anything you actually want to keep, moving it into your own custody is the single highest-leverage safety habit in all of crypto.
Old advice. Still true. Still ignored. Don't be the cautionary tale.
Not financial advice — and definitely never share your recovery phrase.