Each person is born with unique constellation of these three dosha in his or her mind and body. And this pre-set constitution determined at the moment of conception that remains in place throughout one’s life. This is called your Prakriti. And when this prakriti gets out of balance (because of many reasons diet ,lifestyle, accidents, loss , etc) our body and mind suffer from different ailments that is called vikruti (imbalance).
So every person is born different and need to be treated differently according to his/her doshas.