Principles in Refactoring – Slowing Down New Features?

The whole purpose of refactoring is to make us program faster, producing more value with less effort.

and

But I think the most dangerous way that people get trapped is when they try to justify refactoring in terms of "clean code", "good engineering practice", or similar moral reasons. The point of refactoring isn't to show how sparkly a code base is -- it is purely economic. We refactor because it makes us faster -- fastor add features, faster to fix bugs.

-- From Refactoring: Improving the Design of Existing Code (Martin Fowler and Kent Beck), page 56