What a great discussion! Wish it had been done so well (and all in one place) back when I went through the thought process of trying to decide when to pull the plug. Since it's too late for me, all I can offer is my own story.
At 51, my pension vested. At 56, it maxed out at about double the 51 option. Naturally, since I'm a great LBYM saver my NW increased dramatically year by year as well.
Clearly, I could have survived at 51 but I had dreams of something more in retirement than just survival. Additionally, I never "hated" my j*b for more than a couple of months at a time, and I had several multi-year periods when I actually enjoyed it.
I struggled with the exact questions and considerations you all have so eloquently expressed here. When, how much is enough, time vs. money, what then, etc...?
Finally, I calculated (as carefully as possible) what my "dream" retirement would cost and then went for that amount (with lots of safety factors thrown in). Even when I had "arrived", I still hung on because I found myself in one of those really "good" periods at wo*k. Then when everything went crazy at wo*k and my good assignments turned bad, I pulled the plug at 58 with just 3 days notice.
Long story short, I retired almost 3 years ago and moved to my dream spot and dream retirement. I now believe it was all worth it and that I made the right decision. But as I went through the process, it was torture. I found myself second guessing my second guesses. Depending upon the person, that may just be part of what we must go through when making such significant decisions.
So, I guess my advice is to decide what kind of retirement you want, decide how much it will cost and then don't work a day longer than you must to finance your dream.
(If you truly find yourself hating the j*b, forget my advice and pull the plug when you can survive!)
End of lecture.
Happy Lab*r Day!