To determine how many miles you have accumulated in the Frontier EarlyReturns program, members can log into their accounts on the official FlyFrontier website. During the login process, members will need to input their EarlyReturns credentials. Once logged in, they should navigate to the account or mileage section, where they will see their current mileage balance along with any other pertinent details such as recent activity and earned miles from flights or promotions. If a member does not have access to their account or encounters any issues, it is advisable to check for contact information on the website for further assistance. Regularly checking the account can also help keep track of any changes or updates to the mileage balance.