The Total Purchases field displays the total dollar amount the Contact has purchased.
This field is automatically updated when a Sales Invoice for the Contact is saved.
Total Purchases is continually updated unless reset either manually or by using Search & Replace.
The most common reason to reset Total Purchases is to have it represent the total as of a specific time, such as the beginning of each year.
It is not recommended to reset the Total Purchases field.
See:
Contact Database - Main Screen Fields