The New Diversification Rule

How many companies should one invest in? Also, will investing actually make a significant difference for my family in 20 to 30 years? Or is it better to buy the children an investment unit? A couple of big questions there, mate. The benefits of diversification really start to drop precipitously beyond about 20 stocks. Even with 10 stocks, you tend to get like 80% of the way there. So I agree with Buffett, which is always a safe ground to stand on.