If you train a Martial Art, you have a feeling what you practice has been handed down over the space of time. It is especially true if you practice a Kung Fu, like Wing Chun. You believe what your Sifus show you are what he or she was shown, who learned it unchanged from their Sifu, back through time to the ancients.
All arts are evolutionary – all of them. Pre-historic humans used their mouths to spray pigments onto cave walls to paint images of their hands. Today, your printer sprays pigments onto paper to create images of your selfie. An old idea handled in a very new way.
The same is true for the physical arts – the martial arts. Evolution affects the system you study. Evolution is a matter of small mutations, generation by generation. The differing families of Wing Chun bear this out. Is your Wing Chun in the Yui Choi branch, or the Jiu Wan family, or the Yip Man strain? If it is in the Yip Man variety, is it from the early Chan Wah-Shun days or the later Leung Ting era? Each has subtle differences, yet they are all the same, like pigments defining images.
Recognize the art you practice has its roots in the old world, but the variation you study is very new. Some of the techniques you use have not changed, and due to the way the human body works, they will never change, while other techniques are novel and specialized. What you do is old and new.