Brent Simmons writes about how wrong he was to assume that nobody would ever see code he wrote, and how coding with the assumption that other people will eventually work on his code makes him a better developer:

But now I write code with the absolute certain knowledge that it will end up in somebody else’s hands. I could be wrong, yes, but I’ve learned that it helps me write better and more-maintainable code if I just assume from the start that somebody else, most likely a friend, will end up working on that code base.

It’s hard to overstate the importance of this approach. There are very specific coding habits that solo developers tend to pick up, and the longer many developers work solo, the worse they become.