For I have known them all already, known them all: – Have known the evenings, mornings, afternoons, I have measured out my life with coffee spoons; (lines 49-51)
When he says he has "known them all," he wants us to think that he’s an old hand at life. Been there, done that. He doesn’t need new or exciting experiences, because he has had them already. But what exactly is he claiming to have done? Lived through different times of day with the help of a lot of caffeine? Any exhausted student cramming for an exam can tell you what’s that’s like – and it’s hardly the time of your life.
I grow old … I grow old … I shall wear the bottoms of my trousers rolled. (lines 120-121)
He’s starting to run out of steam at this point. He’s like an actor who has to stay on stage even after the play ends. But that’s not going to stop him for convincing us that he’s "The Decider!" He even makes big decisions like rolling his pant-legs. Sounds like a super-hero to us.