We primarily want to use DDD in the areas that are most important to the business. You don’t invest in what can be easily replaced. You invest in the nontrivial, the more complex stuff, the most valuable and important stuff that promises to return the greatest dividends. That’s why we call such a model a Core Domain (2). It is these, and in second priority the significant Supporting Subdomains (2), that deserve and get the biggest investment. Rightly, then, we need to grasp what complex means.
