Calculate in dollar value how much entertainment you get out of Z in a day.
Divide the cost of Z by that amount to see how many days it takes for you to get your moneys worth of entertainment from Z.
Estimate your lifespan.
Deduct the number of days from the second calculation from your predicted life span.
One day later than that, you should not buy.
Example -
You get two hours entertainment value a day valued at say the ten dollars it costs you to go to a movie for two hours. Or perhaps the price of two hours worth of whiskey at the bar. Lets say a daily value of ten dollars for arguments sake or 60 days to get an equal return.
Lets say your health history and family history indicates you will live to be about 78.
Deduct 60 days from the day you turn 78 and if you are older than that, don’t buy. At 77 years and ten months of age, perhaps you should hold off, otherwise?
God I wish I were as young as you and worried about age
Your young enough to do anything you want. Enjoy it.