I rarely carry cash as I rarely need it. Public transport here is cash free. Works canteen is cash free. Almost everywhere else accepts card - even the market stall greengrocer.
And yet every so often I find a shop that won't take cards. I tried to buy a £2.50 item in a shop yesterday. Turned out card minimum was a fiver. Only ATM in the neighbourhood is broken, and I wasn't willing to walk a mile round trip to the next one, so they lost a sale.
Why oh why in 2018 are shops still declining cards as a form of payment?