I hate the concept of retirement, it's just bad in so many ways.
we need a new term, re-time-ment!
It's not about stopping working and being productive, it's about getting control of your time back. To sleep whenever you want, to travel if you want, to be a night owl and work between 11pm-7am, if you choose.
For me, I want to operate on what I call 'kookaburra-time'. Dawn & dusk here in Australia are often punctuated by the Kookas call, signaling to all and sundry that day is about to begin or end. That will enough for me, no clocks or alarms, even the day of the week may become irrelevant.
And of course, if I choose to, I can ignore all that also, on occasion.