Is a token still valid if a user changes their password on eBay? Yes. A token does not become invalid when a user changes their username or password. During the 'change password web-flow', the user is notified that if they wish to revoke token access, they must do so explicity from the MyeBay-> Preferences -> Third Party Authorizations section.
Other situations in which a token can hard expire are:
1. The hard expiration date of the token is reached.
2. eBay expires the token due to security concerns.
In scenario 1, the 3rd party application will receive token Hard Expiration Warnings starting 7 days prior to the scheduled expiration date. In scenario 2, the 3rd party application will not be notified of the hard expiration.