Parents of young children don't get days off.  It sounds trite and obvious, but not until you become a parent of small children do you understand the stark, relentless reality of what 'no days off' means.  It means no weekends, no sick leave, no mental health days, no impulse activities, no dropping everything at a moment's notice.  You're on 24 hour shifts every day and there's no paid overtime.  The younger the children are, the harder it is to find people who can actually replace you...