Whiteboard Fridays (on Wednesday): How to properly size your backup repository

I’m in the USA in these days, and part of my activities has been to stop by our Atlanta offices, I had a couple of meetings there, but the main reason has been to attend as a guest to the Whiteboard Fridays. These are live transmissions from the Atlanta offices, hosted by Jose Mendoza and Shawn Lieu plus some guests that join them from time to time, and the topics are usually deeply technical, and there is an extensive use of whiteboarding. No slidedecks, no recorded video, only a whiteboard and a pen.
This time, is about Veeam backup repositories, and how to properly design and size them!