I do, 99% of the time.
Just arrived at a children's activity without anything as the afternoon went a bit off schedule and now I'm wincing at paying for a drink and snack for them when I've loads at home.
I'm not sure when this happened, but I've become inexplicably tight. Perhaps I enjoyed not shelling out £20 a week on kids snacks during lockdown and just can't bring myself to do it again.
Do you BYO, where do you draw the line?