Agree with others that it's bad advice. At my last job I gave about 5 weeks notice which my manager convinced me to extend to 6 weeks. I was a manager and timing at the end of the year was not ideal due to performance review schedules and holidays.
Never again. Everything was much more dragged out. Lots of idle time. Lots more "so I hear you're leaving" conversations. Next time, I might do one week notice since this seems to have become a lot more common.
I've seen people give management 1-2 months notice and only make it broadly known for the last 2 weeks. Obviously depends on how much you trust management, but it can avoid that awkwardness.
Never again. Everything was much more dragged out. Lots of idle time. Lots more "so I hear you're leaving" conversations. Next time, I might do one week notice since this seems to have become a lot more common.