Ran self-serve water vending machines for a while charging per-jug — $1.50-2 a fill. Volume was fine, but revenue was a rollercoaster: rainy week, slow week, no income. Customers also hated pulling out cash/card every single visit.

Switched to a flat monthly membership for unlimited refills. A few things happened:

• Revenue went from lumpy to predictable — I know exactly what's coming in every month

• Customers refill more often since it's already paid for, which means more foot traffic near the machines (good for anyone else selling near your station)

• Churn is low because $19.99/mo for literally unlimited water beats buying jugs at the store, and people don't cancel over a rainy week

If you're running any kind of vending or self-serve physical business, the lesson translates: stop pricing per-use and start pricing for access. People pay for certainty, not transactions.

Happy to answer questions if anyone's running a similar route/vending setup.