Quitting ASAP doesn’t always make sense. For example, if you’re a month away from meeting your company’s 401(k) “vesting schedule” — that is, when your employer’s 401(k) contributions become yours — you might want to hold off. You might also want to wait if you’re about to get a bonus or your PTO is about to reset.
The same goes for projects. Williams says, “If you are on the very tail end (less than a week before completion) of a large project, try to see that through before resigning. There’s nothing worse than announcing you are quitting while everyone is knees deep in an assignment.”
In addition, she says it’s important to give sufficient notice. “When resigning, you should let your employer know you are prepared to fulfill the two-week notice period. If possible, you can also offer to give an additional week to help with your transition (make sure this added time won’t be an issue with your new employer first, though).”
Source: https://www.buzzfeed.com/eviecarrick/how-to-quit-your-job