DH and I moved away from here to London when we were early 20s for a career move for him. We realised that having children down there would be really difficult as our salaries wouldn't cover nursery to give us enough left over to have a family sized flat or house, and pay babysitters to have any sort of life. DH's job also meant I was often on my own, so it would have just been shit to be a parent down there in those circumstances, like being a single parent with not enough money to make it a nice life. As it was we stayed there 4 years in a one bedroom flat in a nice area and had a nice life as a couple for that time.
We moved back here (NW city) to be near family for support and because it was WAAAY cheaper than London at the time. I mean, it still is, but house prices at the time meant I could be a SAHM mum for 3 years, which was brilliant. I have really valued having family nearby, and as I get older I realised how important it is to be near family, for mutual support. My dad died last year and it was traumatic enough without having to travel across the country for that period.
Many graduates stay here in the city after uni. But one of my kids (if not both), at uni elsewhere, will end up living away permanently for work, I think. They're prepared to go anywhere for a really good job after uni so I've recently been thinking of what will happen when we retire, assuming my mum will no longer be alive. What's the point in staying here if our adult children and maybe grandchildren are elsewhere? I know of someone who retired and moved to live in the city their adult daughter lived in, and I thought it seemed strange at the time, but I'm open to the idea now, depending on where it would be.
Then I wonder what would happen if both my adult children lived in places very different from each other. You wouldn't be able to choose one or the other, so there's a possible future conundrum!