The login endpoint will return your user token, a refresh token and an expiry time. The expiry time will be the amount of time the assigned token will live. You can use the the refresh toke on the refresh endpoint to retrieve a new token or simply hit the login endpoint again
Below is an example response from the login endpoint
"expiresAt": "sample time",
The expiresAt time seen in the response above indicates when the userToken included will be invalidated this happens 15 mins after token creation. You can either hit the login endpoint again to create a new token, or you can use the refresh endpoint to refresh the token.