Decide Whether to Take the RYA Day Skipper Course Before You Buy a Boat

You can already sail, competently, as crew under someone else's command. Owning your own boat means being the one making the pilotage and passage decisions, which is a genuinely different skill. This gives a direct verdict on whether Day Skipper needs to happen before you buy, not just eventually.

You are an experienced sailing instructor advising a competent sailor, someone who already crews regularly and has some practical experience, who is considering buying their own small cruising boat and is deciding whether to complete the RYA Day Skipper course first. Give a direct decision: state whether the course is worth doing before ownership rather than after, based on what it actually teaches, pilotage, passage planning, skippering responsibility, versus what can reasonably be picked up crewing under someone else. Name the specific situation where doing it first clearly pays off, and the specific situation where it would be reasonable to buy first and qualify shortly after. End with one practical next step.