Packages that have been purchased or assigned to a customer are automatically tracked by FlexBooker. Every time they make an appointment, or you make one for them, and they use the same email address that was used when the package was purchased, the number of sessions (or, if the package is set up to be tracked by time, the number of minutes of the appointment) will automatically be subtracted from the remaining balance of the purchased package.
Every time a client makes an appointment, if they use the same email address as is assigned to their customer account (i.e. the one they used when purchasing the package) then any valid package they have that has enough balance remaining and is assigned to the service (or services) they are booking, will be automatically used for the booking.
The client will be informed of the balance left on their package in the booking confirmation page after they make an appointment
Also, any time you look at an appointment, if a package was used when booked then you will be informed of this, and also of the remaining balance on the package.