Forgetful

Bill's wife started noticing how forgetful he was becoming.
Being the concerned wife, she convinced him to see a doctor.

Bill was a little worried when the doctor came in. Sensing
his patient's nervousness, the first thing the doctor did
was to ask what was troubling him.

"Well," Bill answered. "I seem to be getting forgetful. I'm
never sure I can remember where I put the car, or whether
I answered a letter, or where I'm going, or what it is I'm
going to do once I get there, if I get there. So, I really
need your help. What can I do?"

The doctor thought for a moment then answered, "Pay me in
advance."