Short answer: yes — effectively unlimited for normal 2FA use, because most sites store the credential rather than the key. Passwordless sign-in is the exception, with 25 to 100 slots. The number that matters is how many keys you own, not accounts.

Short answer: Account settings → Security → two-factor authentication, and pick the authenticator app over text or phone call. Then sellers should verify their deposit bank details — that’s what a shop takeover is actually aiming at.

Short answer: Airbnb has no authenticator-app toggle — it verifies unfamiliar devices by SMS or email, and supports passkeys on many accounts. So the work is different: add a passkey, secure the email behind it, and hosts should check payout details monthly.

Short answer: smishing is phishing by text, vishing is phishing by voice call. Both bypass the scepticism people have built up about email. One habit defeats nearly all of it — never act on an inbound message about your accounts.

Short answer: Settings → Security → two-factor authentication, and choose the authentication app over SMS. If you signed up with Google or Facebook, the security you need lives on that account instead.

Short answer: signing in without a password at all — via passkeys, security keys or biometrics. The strong versions remove the shared secret entirely. The weak ones, like magic links to your inbox, just move the problem somewhere else.

Short answer: account.adobe.com → Account and security → Sign-in and security → two-step verification, using an authenticator app. And if the option isn’t there, you likely have a work-managed Federated ID — the security lives with your employer.

Short answer: SSO lets you log in once to one provider and reach many services. It doesn’t replace 2FA — it concentrates it. Secure the identity provider properly and everything behind it inherits that protection.

Short answer: Stripe makes two-step authentication mandatory, so the job is upgrading it — a security key as primary, SMS removed, codes saved. Then audit API keys and team members, because those bypass your login entirely.