I gave everyone a first time freebie. Tell them it was first time freebie. ( But it is not in the policies).
Then a step increase fee structure. Next no show gets charged and is X, then next gets X + Y, then next is (X+Y) + Y, etc until it tops off at what my full cash rate is for a follow up.
Majority of people don't do no shows too often, and most get charged at lower dollar rate that people don't really push back on, but those who are habitual are going to get the escalation of fees. They usually drift away from the practice, but I have 1-2 right now that seem to be okay with reaching towards the full cash appointment rate.
Should my practice get more full in the future, I might decrease the number of steps, i.e. Y is a bigger number.