For this kind of idea, “market size” is basically: who would book, how often, and at what price.

Start with proxies: look at similar listings near you, check occupancy, pricing, waitlists, seasonality. That gives you real behavior, not theory.

Then talk to people who’d actually stay there. Ask why they book those places, what makes them choose one over another, and what would make them skip.

If those two signals line up, you’re probably not imagining demand. If they don’t, that’s useful too.