A POS terminal measures one or more criteria, such as the activity rate of the POS terminal. For example, the POS terminal may measure the number of completed transactions per time, the number of items purchased through the POS terminal per time, the number of upsells accepted by customers per time, the number of customers in a store or the number of customers in the vicinity of the POS terminal. The POS terminal in turn compares the measured criteria with a predetermined threshold. Based on the results of the comparison, the POS terminal determines whether to perform a supplementary process. For example, the POS terminal may perform the supplementary process only if the number of transactions per minute is less than a predetermined threshold.