I handled cash on a daily basis for years and I’ve never seen it take 6 years for a new bill to circulate.
I would assume that we should see some of the 2021 bills by now.
But maybe the lockdowns etc. slowed things up a bit.
Or they are hoarding them.
Lots of places won’t even accept cash any longer. I know I have used my debit/credit cards exclusively for over 7 years. Since we moved to our retirement home 7 years ago, I haven’t gotten any cash from an ATM machine. It could be because the cash isn’t moving through the system like it did in the past that it’s not wearing out for a longer period of time?