简单利息与复利有什么区别？ Simple interest is calculated only on the original principal, giving you the same dollar amount in interest each year. Compound interest is calculated on both the principal and accumulated interest, creating exponential growth. For example, $1,000 at 5% for 10年: simple interest = $1,500 total, compound interest = $1,647 total. The difference grows dramatically over longer periods—after 40年, it's $3,000 vs $7,358!

复利频率如何影响我的回报？ More frequent compounding means slightly higher returns because interest is calculated and added to your balance more often, allowing new interest to start earning interest sooner. On $10,000 at 5% for 10年: annual compounding = $16,289, monthly = $16,470, daily = $16,487. The difference is about $198 (1.2% more). It's not huge, but it adds up over time and on larger balances. Always look at APY (which reflects compounding) rather than just APR when comparing accounts.

什么是APY，它与APR有何区别？ APR（Annual Percentage Rate）是未考虑复利的名义年利率。APY（Annual Percentage Yield）是考虑复利频率后的实际年化收益率。例如，5% APR且按月复利的APY为5.12%。APY始终等于或高于APR。在比较储蓄账户或投资时，请始终使用APY以获得准确比较，因为它反映了您实际能够获得的收益。

为什么尽早开始投资如此重要？ 时间是复利中最强大的因素，因为增长是指数型的。有人在25-35岁间每月投资$200（10年，共投入$24,000）然后停止，到65岁往往比在35-65岁间每月投资$200（30年，共投入$72,000）的人拥有更多资产（假设8%回报）。前者的钱复利40年，而后者的钱平均只复利15年。即使是早期投入的小额，也胜过迟来的大额投入。

每月存款如何加速增长？ 每月存款之所以强大，是因为每笔存款都会在剩余投资期内获得复利。第1个月的$100会复利完整期，而第12个月的存款则少了11个月的复利。在20年、6%利率下，$10,000若无额外存款变为$33,102；若加上每月$100存款则变为$79,679——超过翻倍！持续缴款与复利结合能创造指数型财富增长。

什么是72法则？ 72法则（Rule of 72） is a quick mental math trick to estimate how long it takes to double your money with compound interest. Simply divide 72 by your annual interest rate. For example: at 6% interest, 72 ÷ 6 = 12年 to double. At 8%, 72 ÷ 8 = 9年. At 10%, 72 ÷ 10 = 7.2年. It's remarkably accurate for rates between 6-10% and helps you quickly compare investment options or understand the power of different returns over time.

这些回报有保障吗？ 这取决于投资类型。储蓄账户和CDs提供有保障的回报（即声明的利率），但通常较低（3-5%）。股票市场投资（指数基金、ETFs）长期平均回报更高（7-10%），但并不保证，可能在某些年份亏损。债券介于两者之间。一般规律：更高的回报伴随更高的风险。短期目标（低于5年）应选择有保障的选项；长期目标（10年以上）通常可通过承担更高风险获得更好总回报，尽管年度间会有波动。

我应该先还债还是先投资？ Generally, pay off high-interest debt (credit cards at 15-25%) before investing, because guaranteed savings from eliminated interest typically beats investment returns. However, contribute enough to retirement accounts to get any employer match—that's free money (often 50-100% return). For moderate-interest debt (4-7% like mortgages or car loans), the math is closer: if you can reliably earn more investing than your debt interest rate costs, investing may be better. Also consider psychological factors—some people sleep better debt-free even if the math favors investing.