How it works
In the made-up town of Lantern Bay, Nia had twenty spare coins and owed Bea twenty coins, and Bea charged two extra coins every month.
Dov's orchard co-op said coins planted there grow about one coin a month, on average. Some months give more and some give less.
The debt's extra is a sure cost, because Bea charges it every month. The orchard's gain is a maybe, because an average is not a promise.
Other things matter too: a safety jar for surprises, whether the debt nags, and when coins are needed. Families weigh them differently.