If you only store your own notes 1TB is more than enought.

Some storage is needed but not mutch.

Other use cases:

-Proxy for blocking ad's and anything you want.

-Home media server

-Build website/learn/host locally

-Turn it into retro game emulator

.... List continue's, just start with something, figure out what you need to learn and keep it going, its fun. Or dont if you find out its not for you.