> what is my service level objective?

There are environments where flat time distribution for SLO calculation is not acceptable. (cough betting exchange)

If your traffic patterns are extremely spiky, such as weekly peaks hitting 15-20x of your base load, and where a big chunk of your business can come from those peaks, then most normal calculations don't apply.

Let's say your main system that accepts writes is 10 minutes down in a month. That's easily good for >99.9% uptime, but if a failure + PR hit from an inconveniently timed 10-minute window can be responsible for nearly 10% of your monthly revenue, that's a major business problem.

So when setting SLOs, they should be set according to business needs. I may be a heretic saying this but not all downtime is equal.