Odoo 14 Enterprise

We are exploring the idea of using Odoo's AI feature to store financial documents associated with our accounting module (see, for example, https://www.youtube.com/watch?v=Ayab6wZ_U1A).  I am concerned, however, with the cost and space of document storage.  This week we emailed copies of receipts for the first quarter and those emails took up more than 100MB of space.  I can see the space requirements growing over time and, with it, the cost of online storage.

I would be interested in hearing from Odoo users who have used online Documents storage whether they found it relatively affordable (for whatever country they are working in).  Did you find that, periodically, you needed to either delete documents to free up space or perhaps store them onto other media (DVDs, etc.)?  Should we consider the storage of financial documents something we do on a short-term basis and then delete them or do we store them over the longer term (for, say, government record keeping compliance)?  

Thank you in advance for sharing your experience relating to Odoo Documents storage.