In a world where investors are constantly bombarded with market updates, earnings reports and breaking news, the temptation to act is often overwhelming. Yet, one of the most successful value investors, Joel Greenblatt, offers a simple but powerful reminder: "When it comes to long-term investing, doing 'less' is often 'more.'"Patience over constant actionThe quote underscores a timeless principle of investing, that patience often outperforms constant activity. Many investors believe frequent buying and selling, chasing market trends or reacting to every headline can boost returns. However, history has shown that excessive trading often leads to higher transaction costs, poor timing decisions and emotional investing.The power of compoundingLong-term wealth creation is typically driven by staying invested in fundamentally strong businesses and allowing the power of compounding to work over time. Investors who remain disciplined through market volatility are often better positioned to benefit from economic growth and corporate earnings expansion than those attempting to time every market move.The value investing approachGreenblatt's philosophy also aligns with value investing, which focuses on identifying quality companies trading below their intrinsic value and holding them until the market recognises their worth. Rather than constantly reshuffling portfolios, successful investors often spend more time researching businesses than trading their stocks.Avoid emotional investingThe message is particularly relevant during periods of heightened market volatility, when sharp price swings can trigger impulsive decisions. Instead of reacting to short-term fluctuations, investors should periodically review their portfolios, ensure their investments remain aligned with their financial goals and avoid unnecessary churn.The bottom lineUltimately, Greenblatt's quote serves as a reminder that investing success is not always about doing more. Sometimes, resisting the urge to act, staying patient and letting investments compound can be the most rewarding strategy over the long run.