Ergodicity

Sports. The harder you practice, the faster you progress. However, if you try too hard, you might injure yourself. Irrecoverable damage at your joints might end your ability to perform the sport well, or at all.-Career. The harder you work, the more chances you have for professional success. However, if you work too many hours for too long, you might endanger your health, marriage, or mental sanity. Once lost, these are hard, if not impossible, to recover. A single negative event can render short-term maximization irrelevant.

Russian Roulette is non-ergodic because the lifetime outcome differs from the population outcome. If you decide to keep playing it because you fail to grasp its non-ergodicity and mistakenly believe that your lifetime outcome equals your population one, you will end up dead.

If the population and lifetime outcomes differ, the system that produces them is non-ergodic.

You can only rely on expected outcomes if you are guaranteed a large number of repetitions.

The barbell strategy consists of exposing most of yourself to safe activities and a tiny bit of yourself to risky ones with high upside.