nearly every assumption I usually see baked into a user model is eventually invalidated. and adding caching columns like "num of actions" are pretty common too

nearly every assumption I usually see baked into a user model is eventually invalidated. and adding caching columns like "num of actions" are pretty common too, but that tends to mean your whole (fat) row is frequently invalidated, thrashing a bunch of caches. break apart your user tables! if you have constraints on pieces of info, put the constraints there, not on the user!