When you are waiting for certain processes, you are in work. You are unavailable for other activities such as gardening, picking up the kids from school or meet

When you are waiting for certain processes, you are in work. You are unavailable for other activities such as gardening, picking up the kids from school or meeting friends. Well strictly speaking anyway ... but even if you can wangle your way to these things you're still on the hook for work and if something comes up you have to respond. This is all billable time IMO.