I gave 4 YEARS notice. Please don’t bury me...not bragging here, but I knew I would be very hard if not impossible to replace. Part of the issue was that my next in line was older than me, by 10 or 11 years and was planning his own retirement. When I retired, my goal was to replace BOTH me and my next in line, with only one person. As it turned out, we found a replacement for my next in line and gave the older gentleman an easy way out...nice package, consulting for a couple years...just show up a couple times a week, slap a few backs, and read the paper. The new guy was younger than me. After a couple of years, he was suspected of having his hands in the cookie jar (female employees, not money) but nothing was proven, and I’m thinking that could have been because of the women’s fear, or just because they liked being charmed by him. It was in a different country and a different culture. Anyway, his performance, while very good at the beginning, was also beginning to suffer. All this was coming together in my final few months. So when my time came, HQ decided to send a replacement for me, who didn’t speak the language, understand the culture, nor understand the sacrifices made to get to the successes we were having. My underperforming #2 who we had intended to take both roles was gone in short order after that, and my replacement was gone within 3 years...himself also proving to be a bit of a womanizer. I should mention that I was the head of the Asian subsidiary of a large global company, and spoke/speak the language of the main country for that business, understand their culture to the extent possible by a westerner, yet understand the western corporate culture as well. My #2 couldn’t wrap his arms around the global corporate culture. The western guy who replaced me when I retired couldn’t wrap his arms around the Asian cultures. Result=> failure all around. Sales faltered. Profits and more importantly profit margins faltered. About that time, I stopped looking at the results and sold my remaining stock (good thing...it went down quite a bit 6 months later).
Point is this, if you are mission critical and there is no one else who knows how to do what you do, I’d say you owe it to them (especially if you’ve been there a long time) to give them a longer notice. You may want to start the conversation carefully and gently...like “I’m getting older, now xx years old...when do you think I should start thinking about retirement?” Then take it slow and easy from there. Another consideration is if they plan to close your office, when might that happen, and how gold would your parachute be? Depending on the answer to that, I might just keep quiet and see what happens.