A gym offers monthly access or pay-per-visit. Why do many light users choose monthly?

Answer: They overestimate future visits

They overestimate future visits ✓ — Right. In the classic health-club data, many monthly members attended so little that pay-per-use would have been cheaper for the same visits. The key mistake was not arithmetic at signup; it was believing future-you would go much more often than past-you actually did.

Gyms hide the per-visit price — Not quite. Hidden pricing is not needed to create the puzzle. Even when consumers can compare usage-based payment with a flat plan, the imagined, more disciplined future self can still make the monthly option feel sensible.

Monthly builds stronger habits — Not quite. A monthly plan can feel like commitment, and commitment can help some people. The trap here is more specific: light users often price the plan using hoped-for habit formation, then attend less than that hoped-for version of themselves.