Only experience with the same problem space can make you accurately predict where a bottleneck is going to be. Premature optimization will have you focusing on

Only experience with the same problem space can make you accurately predict where a bottleneck is going to be. Premature optimization will have you focusing on areas where optimization isn't required. YAGNI applies to all levels of development. I would rather see bloat and new ideas, than only experts working in a problem domain. My best ideas come from a marriage of understanding a single problem space, and a wonder what I can do in another. Bring on the bloat.