#mystocksquestion An investor with nearly four years of experience in U.S. stocks and ETFs reflects on their biggest investing regret: selling winning stocks too early for modest 20%–30% gains, while holding onto losing positions for too long. This experience highlights that knowing when to sell is often harder than picking stocks. To build a better strategy, they are seeking specific signals that long-term investors use to sell performing assets, wondering whether to focus on valuation, fundamentals, portfolio rebalancing, or simply holding through market volatility.