Whereas price extremes have no boundaries, they don't last forever, eventually commodity market supply and demand factors will bring prices back to a more equilibrium state. Accordingly, while caution is warranted at extreme levels it is often a good time to be constructing counter trend trades as it could be one of the most advantageous times in history to be involved in a market. For instance, similar to the idea of call options being over-priced when a market is at an extreme high, the puts might be abnormally cheap. Once again, your personal situation would determine whether an unlimited risk or limited risk option strategy should be utilized. Please realize that identifying extreme pricing scenarios is easy, it is much more difficult to predict the timing necessary to convert it into a profitable venture.
If in six months the market crashes by 20% (500 points on the index), he or she has made 250 points by being able to sell the index at $2250 when it is trading at $2000—a combined loss of just 10%. In fact, even if the market drops to zero, the loss would only be 10% if this put option is held. Again, purchasing the option will carry a cost (the premium), and if the market doesn’t drop during that period, the maximum loss on the option is just the premium spent.
When buying or selling options, the investor or trader has the right to exercise that option at any point up until the expiration date - so simply buying or selling an option doesn't mean you actually have to exercise it at the buy/sell point. Because of this system, options are considered derivative securities - which means their price is derived from something else (in this case, from the value of assets like the market, securities or other underlying instruments). For this reason, options are often considered less risky than stocks (if used correctly).