Sound advice. Anything to do with accounting, you’ll probably want to treat as an append-only log of events. (Note, you can also use event-sourcing and have your domain entities _be_ events, in a billing bounded context that might make sense. Not usually the first approach I’d recommend though.)
On a similar note, make sure you think about bitemporality as well. In other words, “effective_at” vs. “”created_at”. You might learn that due to a bug, you didn’t record a billable event, and you need to insert it into the history (say, to put it in the correct billing period). But setting the “created_at” in the past brings a bunch of issues; it’s confusing and you’ll soon hit issues where lying about created-time trips you up. (Migrations, reasoning about what version of the code applied what events, etc).
On a similar note, make sure you think about bitemporality as well. In other words, “effective_at” vs. “”created_at”. You might learn that due to a bug, you didn’t record a billable event, and you need to insert it into the history (say, to put it in the correct billing period). But setting the “created_at” in the past brings a bunch of issues; it’s confusing and you’ll soon hit issues where lying about created-time trips you up. (Migrations, reasoning about what version of the code applied what events, etc).
Fowler has good further reading here: https://martinfowler.com/articles/bitemporal-history.html.