Storage costs are certainly something to be weary of, and something I have always hone through great efforts to minimize. We have just over 5GB of total storag

Storage costs are certainly something to be weary of, and something I have always hone through great efforts to minimize. We have just over 5GB of total storage in our org and are only using ~45MB after a year because we planned out model around both storage efficiency and a sane data model. You don't use fully normalized database designs in Salesforce if you can avoid it.