Why such a large NAS?

I would want to get a large capacity NAS system for one reason, and that would be backups. With me backing up two computers, there will be a need for a good capacity NAS. The main reason for this is due to Comcast’s cap on data with their internet service which is limited to 1.2TB.

Another purpose the NAS can serve is to store files that would not be needed often, but need to keep This could be documents, or letters that I have.