I have a plan for a young person. Put 10% of stock/etf money every month in to TQQQ. It grows faster than your other ETF but will lose faster. Luckily the stock market is growing more days than not. If check frequently and if TQQQ has grown to 20%, you sell one quarter of your holding and buy safe ETFs. But keep putting that 10% per month in. Even when it drops. And it can drop like 75%, it might even go nearly bust and lose 95% or more. But keep putting that 10% in. It will grow back rapidly. When it gets to 20% of your portfolio again, cash out a quarter, put it in safe ETFs.

So TQQQ big growths provide a money a rapid money generator to put in your other ETFs. But you lessen the risk by only putting 10% of your fresh stock/etf investing money in to it, and also never letting it grow beyond 20% of your portfolio.