(1) Vending machine must be self-explanatory and accessible to a vast array of users without prior training
(2) Vending machine must offer efficient service with no tolerance for human error
(3) It should successfully dispense the desired selection of snack at any point of time
(4) Vending machine should maintain the quality of the snack from the point when it’s stored until its dispensation
(5) Snacks stored in the vending machine must be available 24x7
(6) Imperative for vending machine to return the exact change to the user to ensure that users do not overpay for the snack