For Ailsa, the big "should I stay or should I go?" decision came at a Gateshead bus stop.
"I thought 'this is not for me,'" she said, thinking about a future of unsecured jobs in a time and place where "industry was dead".
So she became the first in her family to go to university and then moved to London and left her home town behind.
But the decision whether to chase better-paid jobs in the capital has become a widening social divide.
The Social Mobility Commission has published a report showing "stark inequalities" between those who can afford to move to London and the south east of England and those who stay behind in other parts of the UK.
Those "movers" who typically arrive in London in their twenties on average earn 33% more than "stayers", says research from the Institute for Employment Studies, published by the commission.
When people from disadvantaged areas do move, it is four times more likely to be to another deprived area, rather than moving somewhere wealthier, says the research.
Ailsa Weymes, now in her early fifties, bucked the trend and went from a council estate in the North East to university and then a job in banking in London, before teaching and then the civil service.
"It wasn't the norm," she said and remembers people in her home town thinking her university ambitions in the 1980s were "a bit uppity".
Her dad had been unemployed and she says if she'd decided to stay, she might have got a job as a secretary, but the options would have been narrow.
"I didn't see a future," she said of her old home town - and her school had "no expectations for people from the council estates".
"I felt the burning injustice of that," she said.
Now living in London she sees how hard it is for the next generation to move to get better-paid jobs in the capital.
Whether renting or buying, it's very expensive to live in London - and entry points to jobs, such as unpaid internships, can depend on young people having someone else to support them.
She gives talks in schools encouraging children to think about a wide range of careers, as part of the Inspiring the Future project, run by the Education and Employers charity.
The charity's chief executive, Nick Chambers, highlights an unexpected opportunity raised in the social mobility report - that the increase in working from home during the coronavirus pandemic could lead to long-term changes in how people work.
"Many more employers are embracing flexible working arrangements and this will make it much easier for young people to access a wider range of jobs without relocating," said Mr Chambers.
It means a "London" job could be accessible beyond the range of a daily commute.
But the Social Mobility Commission research shows how much upwards mobility currently depends on starting out with an advantage.
Among those moving to London and the South East, 56% are graduates and 60% have a parent in a well-paid job.
But there are downsides to the move to London, says the study - with a higher cost of living and the risk of a weaker sense of community.
It means the move to get better opportunities might come at the cost of friends and family.
"We are all very close," said a mother who was one of the "stayers" interviewed by researchers.
"So the thought of not having that community around you to look after the kids… or even just get together as a family, was massive for me."
"You're so used to a certain area, and then you just go somewhere else, you'd feel a bit lost. I know I would, because I don't like being out my comfort zone," a young person told researchers.
There were also those who thought family priorities were more important than money.
"I feel the job I'm in just now suits my circumstances, in the sense that I've got a good work-life balance. Could I strive to do better? I could, but I wouldn't," a parent told researchers.
For one affluent man in his thirties, moving was almost an inevitability.
"I just kind of assumed, to be honest. Both of my parents are graduates and nearly all my friends' parents are graduates - we always knew we'd move away. You will leave because that's what you do."
Justine Greening, former education secretary, is now running the Social Mobility Pledge campaign, which gets businesses to widen opportunities.
For her, the big fork in the road that meant she was leaving her home town of Rotherham was when, in a phone box, she got her A-level results and knew she was going to university.
She said she was "completely aware" of the significance of the moment - and that having seen her dad being unemployed, she knew the seriousness of such an opportunity.
Growing up, she said she had wanted to know why their family couldn't move to an area where there were more jobs, and had been told by her dad that they couldn't afford the house prices.
But Ms Greening says she wishes that people didn't have to leave their own areas to get ahead.
"I would have liked to have had the chance to stay local," she said, and still thinks of Rotherham as "home".
But at present opportunities can be hard to come by in some parts of the country - and a sense of unfairness can be "very corrosive," said Ms Greening.
"Advantage accumulates - and so does disadvantage," she said.