The skin is our largest organ and by far the most visible. Besides many other functions (sensing, thermoregulation, communication, shielding) it also acts as a protective covering. This means that it receives all the "blows" it is subjected to on a daily basis, throughout our lives: pollution, extreme temperatures, exposure to the sun, contact with various substances, more or less important aggressions.
As well as external influences, the skin also reflects what is going on in our body. Diet, lifestyle, rest or lack of it, all ultimately reflect on the health of the skin. Add to this the changes brought about by the normal ageing process and you will find that our skin is extremely resilient.