Manager asks employee to give the company 3 months' notice before she starts her new job, which starts in 4 weeks: 'I don't feel like I'm obligated to put my next job on hold for them.'

3 months is a ridiculous amount of time.

There is something extremely awkward about the two weeks after you tell your boss you're leaving the company for good. Usually, there's a lot to do… telling your coworkers how to complete tasks you know only you can do, finishing up projects as best you can, and saying goodbye takes up loads of your time.  If that wasn't enough on your plate, your last two weeks at a job often consist of dodging dirty looks from bitter bosses and colleagues who can't stand that you're moving on to greener pastures. When you were devoting all of your time and energy to them, you were a perfect angel who could do no wrong. Now that you're a lame horse to them and a baby mare to someone else, you're more worthless than the dirt on their shoe.

Not every workplace wants you to leave as quickly as possible after giving your notice. Some of them want to keep you on for as long as they can possibly hold onto you. It's not unheard of for employees to give four or six weeks' notice before they leave their company, because they know they won't be able to find a suitable replacement in only two weeks, and they're trying to be as considerate as possible. If you're a super high-level employee, you might give even more notice, but that shouldn't be necessary if you're just a regular employee. 

The employee in this Reddit story tried to give her two weeks' notice at her company, but they wanted much more. They wanted her to stay for the next fiscal quarter.