Where on earth does he say that? There is no shortage of development in any given project. Writing my own http client/server, json parser, html parser, networki

Where on earth does he say that? There is no shortage of development in any given project. Writing my own http client/server, json parser, html parser, networking IO library, and a whole host of other stuff doesn't help me ship faster. I may experiment with implementations of these things on my own to learn more about them but: 1. Doing my own implementation of any of those things is a large amount of effort that isn't directly relevant to my needs in any given job. 2. My first attempts are going to be buggy and incorrect providing a source of bugs in my system that I didn't need. It would be irresponsible to use them in a work product. 3. I don't learn substantially more about software development doing these. I may learn more about http, or json parsing but I'm doing so at the expense of learning more about my business domain. There is some minimum amount I need to know about these things to do my job. The rest is unnecessary until I run into a situation requiring me to dig deeper. To borrow a Software Architecure truism? YAGNI, You ain't gonna need it. It is a fact that I am deliberately limiting myself if I force myself to understand every layer of technology I need to leverage in order to do my job rather than specializing. I will always have to delegate some of that to someone else who has the time to go deep enough to provide a robust solution for me. I will also always have a responsibility to go deep on some of those things when it is relevant to my work.