Do we need to be flexible in life?

There’s a passing phase that hits me every few months. It’s the sense that everything I do will shortly be rendered obsolete and I’m going to have to retrain or retire to a Curmudgeons Home with a load of other inflexibles.
Just me and George Hook shouting at young people going viral. (Actually he’s probably way more adaptable than me). What’s the age you start looking over your shoulder? I hope it’s not yet but I don’t know when it is and the fact that I don’t know when it is makes me look over my shoulder.