Future utility can’t always be predicted

A discount now for future utility is not money saved.

E.g. You buy a pack of 24 car washes at 25% off today. In your mind you think it’s an investment and all you have to do is wash your car more than twice a month to end out ahead for the year.

The problem is you can’t predict the future. You don’t know when you’ll have time to wash your car or if the weather will permit.