[byoung2]

Always give 2 weeks, no more, no less. If you give too much notice, there is the chance that they terminate you right away (you are not invested in the company long term, why keep you), or as soon as they find a replacement (what if that happens quickly). I have worked for companies where as soon as you put in your 2 week notice they just pay you out 2 weeks and terminate your employment that day.

[cableshaft]

While this is generally true, there are situations where departments cannot afford to lose you (yet are handcuffed by the higher-ups to the point where they can't incentivize you to stay), and if you know for sure you're in that situation (usually that's less true than you think), then maybe giving them some extra notice would be good.

But you shouldn't feel like you have to, it's on the company for not being better prepared and having some contingencies and some knowledge and responsibility sharing of some sort in place.

Like someone at my job just gave three months notice today, and my company would be insane to let him go early. They are utterly reliant on him. And it will take time to train someone to follow in his footsteps.

I hope they do hire someone before he leaves that he can train, and not just let him leave without replacing him like they've done so many other times before, because they would be in deep trouble this time.

Like maybe they lose their clients from missing their contractual obligations and the department will have to shut down trouble.

But if I were in those shoes, I probably wouldn't give more than a month at the very most, though.

The one time I did that, I was the only programmer at a small company, and I felt like I'd be leaving them in a really bad position if I didn't give them more notice.

But it didn't seem like the company took advantage of that month anyway, and didn't hire anyone for me to train during that entire time. I mostly just documented what I did as best as I could for two weeks and then just did my normal job until it was time to leave. But they let me keep working the entire month, and didn't force me out early.

[byoung2]

Look at it from the opposite side...if the company were going to lay you off. They would give you maybe 2 weeks, or payment in lieu of notice. You might get a severance that in theory could cover a few weeks while you search for a new job. But even if you could not afford to lose this job, under no circumstances would they ever give you 3 months' notice.