Comment by valenterry

> The difference is where you stuff the complexity.

Exactly. If it were so simple, why not just put everything in one big file / class? I guess we both agree that this very quickly leads to an unmaintainable mess.

So my rule of thumb is: can a feature theoretically be removed without touching the Order entity at all? If so, then NONE of the features parts can live in the Order entity (or even be referred by it).

That means: the Order entity must know nothing about customers, sales, how it stored or cached, how prices and taxes are calculated, how an order is cancelled or repeated or orders can be archived and viewed.

Because any of those features can be removed while the others keep working and using the exact same Order entity.