My retirement plan would look the exact same as my current situation, just without regular new income (unless I persued something that provided that while "retired").
All my income gets autoconverted to sats, I spend on credit, and at the end of the month pay all my bills via nostr:npub1ex7mdykw786qxvmtuls208uyxmn0hse95rfwsarvfde5yg6wy7jq6qvyt9's Bill Pay.
While there may be other services available by the time I no longer need to work, I assume the workflow will be much the same.