It mostly becomes a problem at scale when you need to juggle tens or hundreds of thousands of 'objects' with unpredictable lifetimes and complex interrelationsh

It mostly becomes a problem at scale when you need to juggle tens or hundreds of thousands of 'objects' with unpredictable lifetimes and complex interrelationships. The cases where I have seen granular memory allocation become a problem were mostly game code bases which started small and simple (e.g. a programmer implemented a new system with let's say a hundred items to handle in mind, but for one or another reason, 3 years later that system needs to handle tens of thousands of items).