I’ve been programming for more than 10 years now, and only recently heard about Primitive Obsession. I’ve been guilty of this now and then. But I’ve also written/extended a library that tackles exactly that. Primitive Obsession is the use of primitive data types (i.e. strings, integers, doubles, etc.) for simple tasks, instead of using small objects. Examples are currency, phone numbers, postal codes, etc. Why would you not use primitive types for this? Surely a simple concept like a postal