[ekiminmo]

I have had the opportunity to both design a complex application from scratch as the sole developer and to be thrown into a complex system developed by someone else (who had since left the company). I have found the same truth: being the original developer makes you 10x (or more) productive than anyone else. It takes a lot of effort to bring anyone else up to that level and it will slow you down as you try. What makes perfect sense to you as the original developer will rarely make sense to anyone else, and understanding is critical to making changes.

Being a 10x developer is always situational. You have to be 10x faster than someone, and that difference in speed should not be attributed to "natural talent" when clear organisational issues already exist to explain it.

[douche]

Having the entire design of a system in your head is invaluable. I'm in that situation with one of the products I work on. It can be frustrating, at times, when there is more to do than one person can handle, and you have to delegate tasks out, so you end up spending much more time explaining how something works and guiding someone else as to how to implement a feature, than it would to just go in and make the necessary changes. Eventually, it does pay off, but it requires constant effort to keep abreast of the changes and document everything.