Usually, yes. Once everything is caught up, compliant, and on software, most clients convert to a monthly retainer. This is a smooth transition, because by then we already hold the full context and history of the business since inception.
We can run it two ways: catch-up first, then convert; or run the retainer concurrently, keeping everything compliant from the day we meet you while we clear the backlog in the background so nothing urgent is held up. And retainer clients can always request once-off or ad-hoc work, scoped and invoiced separately.