Features have a specification cost, a design cost, and a development cost. There is a testing cost and a reliability cost. The more features there are, the more likely one will develop problems or will interact badly with another. In software systems, there is a storage cost, which was becoming negligible, but in mobile applications is becoming significant again. There are ascending performance costs because Moore’s Law doesn’t apply to batteries.
Features have a documentation cost. Every feature adds pages to the manual, increasing training costs. Features that offer value to a minority of users impose a cost on all users. So, in designing products and programming languages, we want to get the core features—the good parts—right because that is where we create most of the value.
” Douglas Crockford, Javascript: The Good Parts
