Do JW's believe what Joseph Franklin Rutherford taught or only a portion of his teachings?

Dude if you needed surgery and one of the doctors was going to operate on you using methods from 80 years ago and another doctor with today's technology which one are you going to choose? Let me guess the second one. Why? because today's science is not that of 80 years ago! Our Bible understanding today is certainly different than 80 years ago. Just like Jesus' disciples thought that Jesus was going to restore the Kingdom of his Father on earth and later they understood that it is in heaven. Same old same old.........