Parent/Children Drawing Updates

Hello,

i am new to engineering and tend to get the simple yet difficult things confuse. If you ever have a parent/children drawing for updates, whats the best way of remembering it?

Ex: if you have a casting drawing which is referenced on a machined drawing

Ex: if you have a complete finished good along with packaging and let's say a sub component in a finish good changes, will it rev up packaging?

in theory, in my assumption.. if a parent is affected, all children gets affected.. 
if a child 1 gets affected and there are other children underneath it... the parent won't get affected but anything under child 1 will. 

Please help with feedback. I appreciate your time and efforts