The idea is that there's SO much address space -- you should never need to consider a question like: "is /60 to /64 enough for all of my subnets?" when planning

The idea is that there's SO much address space -- you should never need to consider a question like: "is /60 to /64 enough for all of my subnets?" when planning your network. Subnets should be created because they make sense from an organizational point of view. The amount of available bits shouldn't be a practical consideration. Also, remember, NAT is highly discouraged, so you'll (maybe) eat up another subnet if you run something like Minikube on a laptop.