The cost you did not budget for
Ask an operator what an ice-machine failure costs and you will usually get the repair bill. That is the smallest part of it.
What actually happens is that somebody is now buying bagged ice, repeatedly, during service. Someone is driving to get it. Someone is managing where it is stored and how it gets to the point of use. Drinks are slower. If the outage runs long enough, items come off the menu. All of this lands on people who were already fully occupied.
None of that appears on an invoice, which is precisely why it never appears in the ownership calculation either.
Your staff did not sign up to be an ice logistics operation. That is what a failure turns them into.
