Like most things, it depends. I've given employers no time up to 4 weeks. Smaller ones will definitely receive more grace if they have been good to me. And, when I was an employer I tried to do the same for others.
Another note is that I'm always succession planning. Document, share what I'm doing, etc... I learned early on that if I couldn't be replaced, I also couldn't be promoted.
> I learned early on that if I couldn't be replaced, I also couldn't be promoted.
Nailed this on the head.
At the same time, the extra work this requires is often not appreciated by management either - I've seen some (admittedly poor) managers comment on lower productivity due to the documentation efforts.
It may not be appreciated by management in terms of someone saying “wow, your documentation was incredible, here’s that raise/promotion.” But the people who interact with your documentation will appreciate it, which raises your stature in the organization long term.
And management priorities change over time, it’s not uncommon for companies to emphasize documentation more as they mature.
> I learned early on that if I couldn't be replaced, I also couldn't be promoted.
Even as someone who has zero interest in being promoted, I think this is good practice. It's part of helping to maintain a healthy organization. If anyone is actually indispensable, that's a very dangerous situation for the team and the company.
Another note is that I'm always succession planning. Document, share what I'm doing, etc... I learned early on that if I couldn't be replaced, I also couldn't be promoted.