It would be very useful to be able to reward loyal clients who pay by recurring subscription by applying an automatic discount at renewal. For example, if a subscription costs £100 an automatic 10% discount would be applied so the client pays £90 on renewal. If the price rises to £110 the following year, the discount would be £11.
This would reward loyalty. At the moment it cannot be done. I requested this a while ago and was told it would require a significant rewrite of the code. I suspect this would be a popular feature, so Iet's hope it happens soon. I believe this is also dependent upon the payment gateway.