Work out what your cash flow is likely to be over the next five years. Then calculate the monthly savings you will need to cover your expenses and invest. For example, if you’re single, you can probably expect to spend $1,000 a month. Single women usually need $2,000 to $2,500 a month—and they should invest half of this amount in a growth investment fund. This lets their money work for them rather than them working for it. Plus, it is more tax-efficient than putting money in superannuation. If you are married, you could spend $1,500 a month, which is still pretty low. For most men, it’s more likely to be $2,000 and for most women, it’s more likely to be $2,500 a month. But this needs to include essentials like food and bills, as well as saving for retirement and buying investments. If your expenses are higher than $1,000 a month—say you have kids in daycare or you are paying off a mortgage—you might need more.