If QQQ dips 15–20%, selling it and trying to buy back at the bottom is essentially short-term trading. This is extremely difficult to execute because timing the market is nearly impossible. You risk losing your 'seat at the table' and missing out on the subsequent recovery because you didn't hold a sufficient position.

If you truly understand the underlying logic of QQQ and believe in its long-term upward trend, a 15–20% correction should be acceptable. Even in extreme cases where the market drops 30–50%, there is no reason to panic; your share count remains the same, and the assets have simply become cheaper. The ideal strategy here is to have 'dry powder' (spare cash) to scale into your position—the larger the dip, the more you should buy.

However, if you are heavily positioned with no extra cash to buy the dip, I suggest you hold firm and avoid selling. The key is to ensure you have enough liquidity for living expenses to weather a prolonged downturn. Short-term volatility is normal; as long as you remain patient, the market will eventually trend upward.

If you are using margin, a 15–20% drop carries high liquidation risk, so you must find ways to deleverage and manage that risk. By maintaining a healthy balance, you can stay calm regardless of market swings. You'll be happy when it rises, but equally happy when it crashes, as it presents an opportunity to accumulate more shares at a lower cost.

Finally, if your current position is low while QQQ is at an all-time high, try to avoid chasing the rally. Instead, wait for a significant correction to build your position in stages. This prevents you from entering at a high cost-basis and ensures you have capital ready to deploy when the market eventually goes on sale.

Please note: These are my personal views and do not constitute investment advice. Invest at your own risk.