Sessions and token

Hi all,

If I was to create a mobile app connecting to Michael H.s tutorial
ROR3 application… in order for me to implement a always remember
me model, would a user just sign up once and get a token, and use
that same token every time the mobile app runs. Or do I save the
credentials and then log in behind the scenes every time the app
opens, and then use a new token every app launch?