Start with how you actually play.
Some players finish a game and never touch it again. Others replay the same title for years. If you finish and move on, a disc you can trade in saves real money over a year.
Ask yourself how much data you have each month. A single big release can eat a whole capped bundle, and that is before any patches arrive.
Think about storage too. Consoles fill up quickly, and deleting a huge download only to fetch it again is a pain.
Pop into Gamedorp in Centurion and we will talk it through with you.