<VV> Ball Joints on late Models ?

[rich dixon]

I have a 66 Monza and not sure if the ball joints have ever been replaced, my question to the group is there any data that notes the "uppers joints" being more prone to failure than the lower joints? I need to check them on my car and I appreciate the fact they should replaced since that could be 45 years old, however I don't want to change out  part that is still good and has some life left in it. 
 
Any comments regarding this topic is welcomed, along with any tips for a simple removal and install process is welcomed too.
 
Rich