What should be the standard time horizon for holding a mutual fund?

This question is almost like: Should i eat exercise regularly, or Should i eat healthy food. Investing in mutual funds is the most efficient way to to invest in equities which puts your money to work long term.

You can redeem or withdraw from your investments based on your life needs or for tactical purposes based on your individual investment plan. Other than that it makes sense to stay invested in mutual funds over the long term.