After a long spell of rising interest rates, some financial advisers now contend that the time is at hand for a change in money-management tactics.

The economy is slowing, they say, and interest rates are likely to start falling by midyear, if not sooner.If this is actually going to happen, how can savers and investors make it work to their advantage?

First of all, never forget that forecasting interest rates is a guessing game in which no one has all the answers.

You can consult your banker, broker, accountant or brother-in-law for an informed opinion. But, experts or not, none of these people can give you a sure-fire answer.

Of course, an awareness of this uncertainty doesn't obviate the need to make decisions based on your best guess about what the future holds.

Savers with maturing certificates of deposit must pick a new place to put the proceeds. Many people buying houses face a choice between fixed- or adjustable-rate mortgages.

If you have a strong conviction that rates are headed substantially lower over an extended period of time, an adjustable mortgage might look especially appealing.

No matter how hard it may be to practice it successfully, the operative rule in managing your savings is simple.

If you think interest rates are going to decline, you emphasize investments with longer maturities that enable you to "lock in" today's prevailing rates.

That might mean rolling over a maturing three-month or six-month certificate of deposit into, say, one that runs for 18 months, two years or even longer.

Or it might mean switching some cash now sitting in a money market mutual fund into a fund that invests in intermediate- or long-term bonds.

Should rates decline, yields on money market funds would follow them down. Longer-term funds, by contrast, would benefit from an increase in the market value of the bonds they own, and those funds' net asset values per share should rise.

Right now, extending maturities doesn't bring as much potential benefit as it traditionally does at this stage of the economic cycle. It turns out that many bankers also are expecting interest rates to be lower six months or a year from now.

So at a typical institution, you may find that the going rate on, say, a 14-month CD is no higher, or even slightly lower, than what is offered on a seven-month CD.

Still, picking a longer maturity assures you of a known return for a greater period of time.

Is all the time and trouble involved in this exercise worth it? How much difference in dollars and cents does it make if you earn an extra fraction of a percentage point on your money for an additional year or two?

For some people who need every dollar of income they can squeeze out of their savings, the effort may be a necessity. For others, it is a challenge with psychic as well as financial rewards.

If you would rather devote your time to other things, however, there is a strategy to cushion the impact of interest-rate fluctuations on the return your savings earn.

You could simply divide your money into equal short, intermediate and long-term piles. Whenever a CD or other investment matures, you order it automatically rolled over into a new one of the same kind and maturity.

One nice thing about this sort of "no-brain" strategy: It assures that you won't outsmart yourself.