With the recent debacle of the stock market, the funds that have diversified their risk, will be the winners in the end. 

Diversification of risk is something that should be thought in earnest. Even eating one type of  food (i.e. a large meat diet) will put your health in risk.

When is comes to self defense, you really need to diversify your risk. The one time that you need it, you really need to cover all aspects of an attack. If you just train Brazilian Jiu Jitsu, you will be at risk against an attacker who is skilled in stand-up. 

The UFC has shown us that the fighter with the complete skills are the ones that win. George St. Pierre, BJ Penn, and others who have diversified away from their core martial arts have remained winners.

This is why at OC Jiu Jitsu and MMA we put beginners through a program of MMA and Jiu-Jitsu. You never know where you are going to end up when attacked, but at least you will have all your bases covered.