Optimal Retention Policy for Wasabi My company just started testing Wasabi as opposed to AWS S3 storage about two weeks ago, and we are greatly interested in thoughts on this topic as well.
From the info I have it will depend on what pricing tier you have for what constitutes the 'best practice' settings.
If you are using the Wasabi 'Pay As You Go' option it has a 90d deletion policy. Any data you delete prior to the 90d since initial upload is billed at the full active storage rate until 90d is up. We underestimated this and had to alter our backup policies as our costs were on track to be quite a bit higher then Amazon S3 costs. Until we can get more of a feel for how this affects us we have changed our full backup policy from every month to every three months.
If you are big enough >25TB of active storage then you should opt for their Wasabi Reserved Capacity Storage, you get a bit of a discount and they change the deletion policy to 30d as opposed to 90d.
The company I work for does not have the requirements for >25TB as of right now. I am in talks to see if they would allow a smaller reserved capacity (maybe 5-10TB) if we agree to a longer term.