Short answer
It improves cash flow and increases cancellation risk. Write the duration and transfer terms up front and both become manageable.
What it gains you
Payment up front pulls cash flow forward and reduces month-to-month tracking. A client who bought a package tends to continue: they want to use what they paid for.
Planning gets easier on your side too; a ten-lesson commitment makes a better calendar than weekly uncertainty.
What it risks
An unused package is a liability. The conversation with a client who says “I still had lessons left” six months later is the cost of a term never agreed up front.
Refund requests follow. The money is spent, the lessons are not given.
Three terms, written up front
Duration: how long the package is valid. An open-ended package is an open-ended obligation.
Transfer: whether remaining lessons can be passed to someone else.
Refund: whether unused lessons are refundable, and at what rate.
Tracking what's left
“How many lessons are left?” confuses both sides and costs money. The number has to be readable from a single place.
In Bireby the remaining count is not held in a separate counter; it is the package total minus the lessons given. Because there are not two numbers, neither can be wrong.