Is it necessary to keep evolving?

But it made me wonder, is it important to necessarily keep evolving? I don't think so. It is not something you do, it is something that happens with time. But when you don't make efforts to see yourself outside your comfort zone, you stay where you are. And then one day you notice that other people have evolved and if it bothers you, your personality starts to regress. My mother always tells me- keep doing things so that never in your life do you feel that you are behind somebody. And this has actually worked, evolving and being a better version of yourself keeps you confident in life, it especially helps you during your period of self-doubt. Or when the chips are down, you find it easier to deal with tough times. 

(Excerpt from 'Friends, Groups and Growth)