Every line of code added needs to be maintained and makes adding future code more difficult. As our job is to build software, we are too eager to increase technical debt without knowing it. Always ask "how can we avoid building it?"

When you realize it really does need to be built and it is the highest priority, think about how it can be built while keeping cruft down. You can still be fast while keeping the codebase clean but it requires constant refactoring and review and a common understanding between team members.