Cost of Updates
Data and software version updates are usually paid for by the practice in an on-premises or server hosted solution. Because the data is ultimately your responsibility you are required to pay for and ensure the maintenance of these files. Similarly because software updates are a laborious process they are infrequent are require the payment of additional fees by the practice.
In a multi-tenancy or true web-based model the software and data updates are part of the monthly service fee and provided at no additional cost to the end-user.