Knowing that the rules for your first small deployment are not the same as the rules for everywhere, is valuable for designing well. Trying to implement all of those sets of rules in your initial deployment, is not a good idea. There is a general principle that you shouldn't code the abstraction until you've coded for the concrete example 2 or 3 times, because otherwise you won't make the right abstraction. Looking ahead is not the same as starting with the whole enchilada for your initial deployment.