One credit is worth one 24 hour period. Use the powerbank for 5 minutes, that credit is then expired. Use it for 23 hours, then the credit is expired. It's a use it or lose it model, not per minute.A user cannot use the code repeatedly, it's good for one 24 hour period for that one user account. So if there are 20 consumptions available for that code, and you use the credit, it can be applied to 19 accounts after that.