Yes, it depends on the workload. Idempotency is typically always a good idea, but sometimes the operation itself is very expensive in terms of time, resources, and/or money. I have also seen people try to update the message when writing it back(with checkpoint information and etc) for long running processes. A slew of issues, including at least once delivery, can cause workflow bifurcation. Deduplication via FIFO _can_ help mitigate this, but it has a time window that needs to be accounted for. Once you start managing your own deduplication I'd say it has moved past trying to go databaseless.