My GP - none, only 2 left when DC were born, one chose to move to the other end of the country near her DD, the other was crazy (I spent loads of time with her growing up) but whilst she would 'help' my DM I wouldn't have given her sole care
My DP, loads my mum was an old fashioned housewife and n her early 50s when DC were born, she was quite clear that she wouldn't be my childcare (I worked full time) but was happy to cover the nanny's holidays etc plus weekends, evenings if needed. She is local and great. DF not so much as he worked full time then and didn't really do babies. My DC are now grown up but my parents are still there for them, offering lifts, watching over them when I go away without them. I also have young DNephews as DB is considerably younger than me, both DP help out with them too still despite now being in their 70s, they will do overnights and often have just one over for the day to give SIL a break as there are 3 of them and they fight. DDad is in his element with the boys and now he is retired has plenty of time for them.
My PIL were also in their mid 50s when my DC were born and both had full time jobs, they loved weekend sleepovers though, which was perfect for me and having a social life.
They now have also retired and have 4 more GC who they do loads for, roughly 2-3 full days childcare each week including overnights for both their other children.
We all know that we are very lucky.