From my experience doing freelance, many clients simply don't care about maintainable code. In fact, it requires effort on my part in trying to convince them th

From my experience doing freelance, many clients simply don't care about maintainable code. In fact, it requires effort on my part in trying to convince them that it's worth their while to pay the extra time for me to clean up the spaghetti mess I inherited or otherwise to write something with the future in mind. I would imagine that any experienced, self-respecting developer would naturally want to develop sustainable code. Hence, I recommend (a) finding experienced, self-respecting developers and (b) letting them know that taking extra time to make sustainable code is okay. Aside from that, experience in working on or managing larger, long-term projects probably helps. A developer who has never maintained a project for 5+ years may lack awareness of how sustainability mistakes can happen.