Update 3 May 2020: after a bit of a requests bill spike, I had another look at rclone’s options and the S3 storage classes. You can now directly create backup objects with Intelligent Tiering by setting the backend storage_class, which in theory should be much cheaper for frequent backups. I’ll report back on whether it really is!
Update 10 Apr 2021: I think the answer to this is… maybe?! Costs are very slightly lower on average but this also coincides with several months with fewer backups. One thing that is noticeable so far is that the variation is less – I’ve not hit such a big subsequent cost spike again. But this could be down to my behaviour as much as the tiered pricing’s, and of course your mileage will certainly vary!
I recently tried out a new remote backup approach.
Whether you consider it a success will probably depend on your quantity of files, and how much money you have lying around for month #1.