If you can't leave your money in a fund for a period of five to 10 years, you will not have the advantage of allowing your money to work over time. Historically, though, mutual funds have rewarded those who exercise both. If you're investing for capital preservation instead of growth, or if you think you'll need your money right away, consider investing in a money market or other low-risk fund. Mutual funds have varying degrees of risk and fluctuate in value daily.
Mutual funds are excellent vehicles for all three.
But putting money away without a clear goal may not help you in the long run. Consider your goals, timeline and level of risk tolerance when determining which funds are right for you. Though you are trusting a professional manager to handle your money, you want to keep track of how your fund is performing. If you have questions about a fund, call your fund company and ask. Research funds at libraries.