[watwut]

Impact of architectural and design decisions. How hard to decipher certain code parts you are so proud about today are a year later - my experience is that people used to work on small projects or who change projects a lot generate hard to maintain/understand code.

Learning non-trivial codebase often takes much more time. I worked on bigger projects and someone who worked there only six months would not be allowed to do bigger or core changes.

Then there is domain knowledge (finance, healthcare, law, etc) if you do that kind of software. Six months is enough to learn surface in anything non-trivial and everything is much more effective if developer already learned that.

Of course, last two points are not really valid for small projects world.

[Iftheshoefits]

Most of the things you describe are deep, but also very narrow and domain-specific; frequently it is also very company-specific. Such knowledge is far less transferable than one might imagine.

[sheepmullet]

"Most of the things you describe are deep, but also very narrow and domain-specific; frequently it is also very company-specific. Such knowledge is far less transferable than one might imagine."

Agreed. It is the quickest way to become a 10x employee but unfortunately your current company won't give you a substantial raise for knowing their product and domain well and it is not transferable to other workplaces.