Membership and subscription models have become common in detailing, with recurring monthly visits in exchange for a lower per-visit rate. The hard part of any membership model is never the sign-up. It is the renewal, keeping members engaged enough, month after month, that canceling never becomes the obvious move.
A consistent, expected finishing experience plays a bigger role in that retention than most shops give it credit for. Members are not just paying for clean paint on a schedule. They are paying for a specific, reliable feeling their car gets every visit, and a signature fragrance is one of the easiest, most repeatable parts of that feeling to actually deliver consistently.
This works especially well as an expectation members can articulate to themselves, and to friends they might refer. My detailer always finishes with this specific scent is a concrete, sensory detail that is easier to remember and repeat than a more abstract sense of good service, which makes it a surprisingly effective, low-effort piece of a referral-driving membership experience.
It also gives a membership program a built-in reason to feel different from a one-off wash, which matters more than it sounds like for retention specifically. A member who could theoretically get similar paint results at a cheaper one-off shop needs a reason the membership itself is worth staying subscribed to. A consistent, elevated finishing standard, present every single visit without fail, is part of what makes the recurring relationship feel worth the recurring cost.