Scott

That assumes that notes spent at a store are kept and never reused; that’s simply not true. If you buy a €5 coffee with a €5 note and then later in the day someone buys a €3 muffin with a €10 note, your €5 note is given to them as change. Repeat that process in a town or city and that cash gets pretty shuffled quite quickly.

Your scenario doesn’t also take into account till “float” where a portion of cash is kept in the till/store/elsewhere to seed the till the next morning for the first customers of the day, should they need change for their purchases.