A man makes you this deal: He will give you 5.000.000 $ if you give him 10 years of your life. From those 10 years you can still sell 1 year per 500.000 $. He doesnt now when you are going to die nither you do. He only nows 100% that those years you give him will make him live longer, healthier and younger.
What would you do?
He will only agree to buy 10 or more years.