When contemplating the optimal number of mutual funds to include in an investment portfolio, a multitude of factors inevitably arises. How does one ascertain the appropriate mix that aligns with individual financial goals and risk tolerance? Is it prudent to focus on diversification by incorporating a variety of funds across different sectors, or would a more concentrated approach yield better results? Furthermore, should one consider the nuances of fund management styles, such as active versus passive strategies, which could also influence this decision? Are there specific guidelines or industry standards that suggest an ideal range, or do these recommendations vary widely based on personal circumstances and market conditions? Moreover, in the context of fees and expenses associated with multiple funds, how can an investor effectively balance potential returns against the cost of management? Ultimately, what considerations should be prioritized to optimize investment outcomes while maintaining a manageable level of complexity in fund oversight?