I vividly remember the first time I used my phone to ride the New York City subway. I tapped my device against the translucent rectangle thing, the light turned green, and the turnstile made a familiar click inviting me to push through the metal arms. On the other side, the future beckoned. After a two-decade run as New York's preeminent pass to the subway, the MetroCard has officially joined the brass token in the annals of subway history.
You can get through most of London now without touching a coin. The bar, the bus, the cinema, even a takeaway from a late-night chicken shop, tap and go. Most people don't ask if cash is accepted anymore. They assume it isn't. Most of the time, they're right.