Bookings For A Year In Advance

I've just been contacted for maths tuition sessions.
Unfortunately,  or fortunately,  I'm now fully booked and have had to turn potential tutee's away.
This person then asked if they could book for the next academic year September 2017.
This is a new experience for me. They had been given my details as a recommendation from an existing tutee's parents.
It just shows the power of referrals from your existing customers so thanks a lot to all of you that have passed my details on.