Sticker badge, card or keychain: which one?

The three objects are equal: same NFC chip, same QR code, same emergency profile behind them. The only question is where you will carry it.

• The badge sticks to the back of your phone or its case. Your phone is what you have on you most of the time, and it is where a responder looks first. It is the only object that is stuck on for good.
• The card is the size of a bank card and lives in your wallet, next to your ID. It is the one that survives a lost or destroyed phone, and it is where a responder looks when they check for identity papers.
• The keychain rides on your keyring, so it comes with you when you leave with nothing else: a run, a bike ride, a trip to the pool.

Why take more than one? Because you cannot predict which one will be within reach. A phone can be thrown across the road in a crash, a wallet can stay in a locker. Extra objects cost less than the first one (the profile is what you are paying for) and all of them open the same profile, so nothing has to be kept in sync.

If you only want one: take the badge if you are rarely without your phone, the card if you carry a wallet everywhere, the keychain if you often go out with just your keys.