A server system tracks purchases by a user of consumable items. Notifications of use of an appliance using a consumable item are received and an estimated amount of the consumable item is decremented in response to the notification. A consumption rate is determined based on the notifications and an expected runout date is calculated. Delivery of the consumable items is then invoked on or before the runout date. The appliance may include, for example, be a network-enabled washing machine that reports loads washed, a refrigerator that detects items removed therefrom, a coffee maker that reports cups of coffee prepared.