There is a pool next door and two things happen in it. The try dive is ninety minutes for somebody who has never breathed underwater and wants to find out whether they like it, with no theory and no certification.
The refresher hour is for a certified diver with a gap. Mask clearing, regulator recovery, buoyancy and the weight you actually need now. We suggest it past twelve months and insist on it past three years.
Neither is a sales exercise. A diver who is unsure of themselves in a pool is going to have an unpleasant week in the sea.