I think the key is to constantly challenge yourself and never rest on your laurels. It's like strength training — if it's easy, it doesn't do much for your musc

I think the key is to constantly challenge yourself and never rest on your laurels. It's like strength training — if it's easy, it doesn't do much for your muscles. Learn new things, read about new concepts. And always remember, it should be hard. If it's easy, it doesn't do much for your mind.