re: VOO or QQQ

Thanks for the explanation and the link. I guess what I was looking for was some kind of understanding of the long-run trend. For example, are long-run average returns 3x the QQQ trend (ignoring fee difference)? Of course there will be higher volatility in TQQQ--maybe even >3x QQQ volatility, but if you're a young investor with high risk tolerance, why not use TQQQ as a long-run investment strategy? Is the magnified downside disproportionate to the magnified upside, leading to long-run losses in a market without large average returns? If so, is that caused by the high fees or some kind of geometric compounding property? Maybe the answers are not well known.