DC1 who lives 18 miles away, we see around twice a month on average, comes here every 5-6 weeks and we go to theirs every 5-6 weeks, and I meet up with them once or twice in between those times ... Sometimes on my own, sometimes with DH.
DC2 who lives 30 miles away, we see a bit less.. Maybe once a month I would say. They come here one time, then we go there the next. We all meet up together some 4-5 times a year too (like every couple of months maybe...) On mine or DH's birthday, and Christmas, and a couple of other random times during the year. Sometimes on Mothers Day and Fathers Day. On their birthdays they do their own thing with their partner(s) and friends, so we usually try to see them 2-3 days before to give them their gifts and card.
We do speak on around 2-3 days in any given week, on WhatsApp though, to DC1,) and do Facetime. (And one day a week with DC2.) It would be nice to have both DC 10 minutes walk down the road, like a few of my neighbours, and see them twice a week, (like they do,) but it is what it is. They are both University graduates, and professionals, and have busy careers, and busy lives. Lots of friends, and lots of hobbies and interests, and they travel quite a bit. (Both aged 30-ish.) So we know we're not No 1 in their lives anymore, and that's OK. They're adults, who have been independent for over a decade. Left home after leaving Uni and never returned.
I am just happy they're living their best lives, and there's no guarantee that if we did see them twice a week, that the relationship with them would be any better. It's great now, with both. I know that if we needed them urgently/in an emergency, they'd be here as soon as they could get here. They're not too far away. 
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