You might persist that value as an optimisation, but if you make it your source of truth, and discard your inputs, you better make sure you never ever ever ever have a bug in deriveValuedCustomer() or else you have lost data permanently
You might persist that value as an optimisation, but if you make it your source of truth, and discard your inputs, you better make sure you never ever ever ever have a bug in deriveValuedCustomer() or else you have lost data permanently
Good point - you wouldn't want to discard your inputs. You're going to need them should you ever redefine deriveValuedCustomer() - which is likely for a system that will be in production for 10-20 years or more.