It depends on the type of job and personal ethics you have. I told my boss back in March that I will probably be leaving this year so he could hire someone to fill my position & be trained on everything that I do. I've been in my company for 2 1/2 years & they have been good to me, so I'm not going to leave them in the ditch by giving them a sh**ty two weeks notice. It's smart to leave your job on good terms, because if by some small chance ATC doesn't work out, you might have the option of going back until you find something better.