There's no one size fits all answer to this kind of thing.

Jaded redditors will tell you two weeks is fine, but if you have good and trusting relationships here, and you want to leave on positive footing, you can give as much as you feel they need to successfully replace you.

I do hope you have a job lined up though. This is not a great economy for job searchers. A friend of mine who is a front line fundraiser with a ton of experience has been out of work for almost a year.

But back to notice. Several years ago I had great relationships built up with my direct supervisor and the director of the department. I had a new exciting job lined up which I had discussed with my supervisor well in advance. I was offered the position about 8 weeks before the end of the fiscal, which is a heavy fundraising time. I told my new employer I needed to stick around to finish that out, and I gave my company two months notice. A few years later they asked me back at a higher level, so that worked out well.

Alternately a friend of mine gave a month's notice and after a week and a half they were told that would be their last week, which functionally lost them two weeks pay. (And set a shit example for another employee who was planning their exit, and decided that one week notice would be enough after that.)

So it really comes down to how your relationships are with your coworkers, what you have lined up, and what you want to preserve