Good Time To Use Custom Events?

How to implement my own events I'm not sure why do I use them. I mean instead of rising event you could simply call functions right? This is as close as I got to a good reason:
1) If you call a function that does one thing and then based on result it needs to do something else it may be a good idea to do that something else in event function that is raised when that first thing was done. This way you avoid creating long functions and can make system more intuitive.
2) If object1 is inside object2 (a variable) and object2 has function DoThis and in that function affect something in object2's parent class it's better to use event in object1 rather than mess with parent (object1) inside object2.