You don't need to be an expert to write working software. You don't even need to be an expert to write good software - you do need to be knowledgeable in that f

You don't need to be an expert to write working software. You don't even need to be an expert to write good software - you do need to be knowledgeable in that field to write maintainable software, but even experts in the field often write bad software in the name of expedience.