Between a free self-serve check and a delivery programme sit three commitments worth making. They differ by what they produce, not by how long they run.
A review answers the question a leadership team asks: what state is this installation in, and what would it take to put it right. A diagnostic answers a narrower and harder question: within a defined area, which configuration decisions and defects are costing money now, in what order should they be corrected, and what does each correction take. A remediation programme answers neither. It assumes both answers exist and commits people to doing the work.
It is easy to commission these in the wrong order. A programme gets raised because the symptoms are loud, before anyone has written down what the system actually does, and the opening weeks of that programme go on discovering what a three-week diagnostic would have established first.
Ahead of all three sits the free configuration health check on this site: twelve questions, answered in about two minutes, scored on the page, with no email address asked for at any point. It does not size the work. It tells you whether the conversation is worth having.