Tell me what's wrong with my logic-- Let's say we agree to buy SPY whenever it crosses above it's 50 day MA, hold it, and only sell when it crosses back below. If it is in fact true that over the next 50 years, the market will go way up, then it's true that the market will spend the vast majority of those up periods above its 50 day MA. Therefore, if we agree to buy and hold whenever it's above it's MA, then we'll be along for the ride for the vast majority of the bull market. If, however, the predicition is wrong, and over the next 50 years there's a major decline, then the market will spend the vast majority of that decline below its 50 day MA; therefore, because we do not hold the market when its below its 50 day MA, we'll preserve our capital in periods of decline. In conclusion, buying and holding SPY/QQQ in the manner described above will allow you to ride bull trends in the coming days and avoid any declines. Therefore, this simple strategy is better than buy and hold because it allows you all the benefits of buy and hold without the risk. Where am I wrong?