Where are you? In Canada you don't have to give ANY notice to leave. It is done out of consideration for your employer and their need to replace you before you leave.
> After 295 days of hearing, the trial judge found that the defendants had been integral in managing projects and designing the company’s core technology products which formed the backbone of the company. The Court found that these individuals were part of senior management and were crucial to the direction and guidance of the company and as such owed fiduciary duties to GasTOPS. The Court further held that the two weeks of notice of resignation provided by each of the defendants was wholly inadequate, and that each of the defendants were fully aware that their departures would leave GasTOPS unable to fulfill its existing contracts, or continue to pursue the business opportunities it had been cultivating. ...
> On appeal, the Court of Appeal held that the 10-year disgorgement period was reasonable, given the small and highly specialized market, the nature of the confidential and technical information that had been misappropriated and used, and the product that was created and marketed using this information. The Court of Appeal was also influenced by the fact that GasTOPS was an industry leader in a market that only contained a small number of very large customers. Accordingly, it was reasonable to conclude that it would take approximately 10 years for the damage caused to dissipate.
> Although the damage award in this case was extremely large, the Court noted that the breach of fiduciary duties owed in this case were particularly egregious.
> In Aquafor v. Whyte, Dainty, and Calder, the court held the four and five weeks’ notice provided by two departing fiduciary employees was sufficient
But that wasn't a blanket decision. Had Aquafor been able to show the judge that that they needed "12-18 months" (!) notice, then it probably would have had a different result.
[1] http://business.financialpost.com/2012/09/04/when-two-weeks-...