I said "no" in your position (about 8 years ago) and although my son and daughter-in-law couldn't understand why I said no (and were a bit surprised and disgruntled) they quickly got over it and sorted it out without me.
I still help out in an emergency of course and occasionally at weekends.
But no feelings of regret!
Don't feel bad.
Briefing against women ministers in Westminster
Walking sticks in "tottery" in old age
What’s a household item that reminds you of your grandma’s house?


