Do Facebook Oauth 2.0 Access Tokens Expire?

After digging around a bit, i found this. It seems to be the answer:

Updated (11/April/2018)

• The token will expire after about 60 days.
• The token will be refreshed once per day, for up to 90 days, when the person using your app makes a request to Facebook's servers.
• All access tokens need to be renewed every 90 days with the consent of the person using your app.

Facebook change announce (10/04/2018)

Facebook updated token expiration page (10/04/2018)

offline_access: Enables your application to perform authorized requests on behalf of the user at any time. By default, most access tokens expire after a short time period to ensure applications only make requests on behalf of the user when the are actively using the application. This permission makes the access token returned by our OAuth endpoint long-lived.

Its a permission value requested.

http://developers.facebook.com/docs/authentication/permissions

UPDATE

offline_access permission has been removed a while ago.

https://developers.facebook.com/docs/roadmap/completed-changes/offline-access-removal/

Try this may be it will help full for you

https://graph.facebook.com/oauth/authorize?
    client_id=127605460617602&
scope=offline_access,read_stream,user_photos,user_videos,publish_stream&
    redirect_uri=http://www.example.com/

To get lifetime Access Token you have to use scope=offline_access

Meaning of scope=offline_access is that :-

Enables your application to perform authorized requests on behalf of the user at any time. By default, most access tokens expire after a short time period to ensure applications only make requests on behalf of the user when the are actively using the application. This permission makes the access token returned by our OAuth endpoint long-lived.

But according to facebook future upgradation the offline_acees functionality will be deprecated for forever from the 3rd October, 2012. and the user will be given 60 days long-lived access token and before expiration of the access token Facebook will notify or you can get your custom notification functionality fetching the expiration value from the Facebook Api..