Why do stars appear to be permanent to us even though these are born, grow and then die?

The stars appear to be permanent because the physical characteristics of a star like brightness, temperature, colour and size change very very slowly with time as compared to our life span. It takes millions of years for a noticeable change to occur in a star whereas a man stays on earth for 70-75 years on an average. Therefore, a star appears to be permanent even though it is slowly dying.