First of all, please note that token expiration and revoking are two different things.
- Expiration only happens for web apps, not for native mobile apps, because native apps never expire.
- Revoking only happens when (1) uses click the logout button on the website or native Apps;(2) users reset their passwords; (3) users revoke their tokens explicitly in the administration panel.
A JWT token that never expires is dangerous if the token is stolen then someone can always access the user's data.
Quoted from JWT RFC: