As landline usage continues to fall, a new Ofcom study suggests remembering phone numbers could soon be consigned to history.
Between 2012 and 2017, time spent on landline calls plummeted from 103 billion minutes to 54 billion minutes.
Over the same period, mobile calls rose to 148.6 billion minutes.
Throw in the growth of messaging services such as WhatsApp, and could the convention of dialling codes disappear altogether?
As part of its research, Ofcom interviewed a cross-section of consumers, including 14 focus groups.
It found a clear generational shift, between younger people who preferred to use text-based messaging services and older people who preferred to talk over the phone.
"Calling someone is a bit daunting," one 18-year-old told the organisation.
"It's much easier and quicker to WhatsApp my friends. If I have to call a company, I'll always try to use web chat if it's available."
A split was also found in the approach to area codes. In short: the younger people didn't feel strongly about them, and many didn't realise they had any geographical significance.
These codes originally corresponded to the first two letters of a place. Aberdeen, for example, was AB, which equates to 22 on the keypad. Today's code for Aberdeen is 01224.
The older people, on the other hand, found area codes helpful and reassuring when making and receiving calls. "It's helpful to know where things are," said one 67-year-old from Wrexham.
What does this say about the changing ways we communicate?
"We've seen a shift in people, away from thinking of communication as place-based, towards something more personal," Dr Bernie Hogan, from the Oxford Internet Institute, told the BBC.
Time and place
Instead of sharing phones in particular places, nailed to the wall or placed on a desk, we have got used to having our communication hub on our bodies, always at hand for messages, pictures and calls.
Dr Hogan said this does not necessarily mean the landline will disappear altogether. In fact, in an age of smartphones, it may find a renewed sense of purpose. "The landline won't have a resurgence but what it represents might: being available at a certain place and time."
As anyone who has faced late-night work emails or calls will be able to tell you, the bounds around communication have loosened as we've moved away from distinct private and professional numbers.
Instead of memorising different numbers for the office or for home, plenty of people now use the same phone for calls throughout the day. But how does this square with the various roles we inhabit from morning to midnight?
"A person is many people," said professor John Zimmerman, from Carnegie Mellon University's Human-Computer Interaction Institute. "Dad, son, employee, member, etc. Often it is more important for our devices to know who we are in the moment when making a choice to allow, dismiss, or reroute a potential connection."
Unhinged from clunky plastic handsets wired into specific rooms, what lines of communication should reach us when? Are we a manager in our child's bedroom, or a mother in a board meeting?
For many, these roles are increasingly managed by a platter of social media accounts, from your family WhatsApp group to your work LinkedIn account. Unlike an open public network such as a phone number system, however, these are privately owned; controlled by big technology companies.
"What we're seeing is a shift towards the corporatisation of our communication channels," warned Dr Hogan. "It's a concern. There should be policy or legal means to allow for interoperable communication between corporate networks."
Detached from names and private platforms, there's something simple about a series of numbers; a comprehensible digit-based address, pinpointing a line of communication. From webpage IP addresses to GPS coordinates, numbers seethe beneath the surface of our screens, but these are vast and complex, impossible to memorise or to feel a sense of ownership over.
So what will happen? A hipster return of landlines? A resurgence of area codes? Probably not, but as a generation grows up with smartphones in their pockets, new ways will need to capture what that 67-year-old from Wrexham told Ofcom:
"It's helpful to know where things are."