I ask for payment beforehand for therapy and reviews and I have very few cancellations or issues with payment. I think if people have already paid for their therapy sessions they are less likely to cancel. I ask for a deposit to secure an initial appointment and then ask for the balance after the appointment. These are the only occasions where I have had to chase payment. I think it’s completely reasonable to request payment beforehand as there is a lot of work that goes into an appointment prior to actually seeing the client. For families where finance is more of an issue I offer the option of paying one session up front at a time but for most I will invoice either monthly or half termly for all appointments that are booked. No one has ever queried this. If an appointment is then cancelled due to illness, it is a credit towards their next appointments. The only other instances when I invoice afterwards are when I’m not sure how long an appointment will take e.g. for a school visit which includes a meeting after seeing the child or when writing a detailed report (I will give an estimate of the time and then confirm once written).
I hope that’s helpful,