dunkelblau
Recycles dryer sheets
No person is irreplaceable, if it takes more than 30 days for company to transition your responsibilities / duties then you and the company haven't done a very good job of cross training.
Providing a long notice of your retirement seems to be either be that you are really not mentally prepared for retirement or that you are looking to garner attention from your peers and staff.
I gave notice to three levels of management in my chain over a year ago. No firm target date on my part, just that I saw it coming in a few quarters, depending on circumstances. Part of our discussion was my disclosure of what happened five years ago when I applied for a company-wide buyout but was one of very few whose applications were denied. That occurred before we were acquired so my new chain of command wasn't aware.
Apparently they needed the work I produced and couldn't find anyone else to do it. I stayed on with an incentive and spent the next year creating extensive training materials. My niche isn't realistically transferable in 30 days, mainly because we run a lean team.
Maybe I'm not really mentally prepared for retirement (seems easier than starting a new career if I were go guess), but I certainly have not been looking to garner attention from my peers because I didn't tell them, and I've never been a manager.
My motivation last year was to inform my new chain in case an exit opportunity arose that would be convenient to them and hopefully comes with a bit of payout for me. In the meantime they've also gotten in the habit of asking my permission before giving me any new assignments, which is kind of cool. And I still post training materials regularly.