I realize this has turned into a meme thread, but I wanted to chime in.
I will probably work till I die. I don't believe in retirement. I like working.
I am a problem solver by nature, so I will always look for things to fix and people will always pay for that.
I never had the illusion that a company or a team or whatever can't survive without me, but I always knew that I was skilled enough that they'd have to downgrade if they ever replaced me, so I took pride in that and in my work. But I will say this, ever since I became a mom, my perspective has changed a lot around employment. I liked to work and loved being challenged, but it sunk even more that I am replaceable everywhere and to everyone, except to one tiny little human. Then, I truly stopped caring about corporate games, career ladders, challenging assignments, "unique opportunities", and all other bullshit. My career objectives were completely erased after motherhood. So, I worked hard to set up myself financially over 5-6 years, then I quit.
I will probably go back to work when my kid is older, and I will be more selective of where I will contribute, but for now I know where my work matters most, and it's not in the office.