It's known as an investor's worst enemy and the silent assassin of savings. It has even been called "public enemy number one". All these unflattering titles belong to inflation.

A 6% inflation rate will almost halve the value of your money over 10 years - turning, for example, R10,000 into R5,584. After 20 years, your R10,000 will lose 70% of its purchasing power and be worth only R3,118, according to Old Mutual Investment Group.

This is why we need our investments to deliver returns that outperform inflation - what's known as a "real" or inflation-adjusted return.

"Inflation is the most important index," Zain Wilson, a portfolio manager at Old Mutual Investment Group, says, noting that SA has a high inflation target compared to the rest of the world.

The following examples from the Long-Term Perspectives2019 report, published by Old Mutual Investment Group, illustrate the impact of inflation on our everyday lives.

A mid-sized family sedan which sold for R272,000 last year will cost R478,000 in 10 years and R1.1m in 25 years' time. That's assuming an inflation rate of 5.8% which has been the average vehicle inflation rate since 1990.

A year's tuition and boarding at a top private school last year cost R215,000. In 10 years it will cost R518,000 and in 25 years, R1.9m. That is assuming an education inflation rate of 9.2%.

One year of kidney dialysis in a private hospital cost R192,000 last year. A decade from now it will cost R502,000 and R2.1m 25 years from now, assuming a rate of 10.1% medical inflation.

Looking back in time we can see how inflation has pushed up the price of some local favourites: Last year you would have paid R74.90 for a Spur burger; in the 1970s it was 30 cents. A 300g Cheddamelt steak last year cost R159; in the 1970s you would have paid 50 cents. A 750g tin of Ricoffy last year was R80; in the 1970s it was 25 cents.

The variability of inflation is a challenge for budgeting, Old Mutual's report notes.

The inflation rate is an average of all consumers in the country. If your expenditure is skewed towards goods or services with very high inflation rates, such as education and healthcare, your personal inflation rate will be much higher than the country average. In this case, you will need to earn or save more for these future expenses.

If your retirement income - whether you buy a guaranteed annuity or draw from investments - does not at least grow in line with inflation, you will either experience a decline in your standard of living or you will run out of money before you die.

At a 6% inflation rate, a fixed monthly retirement income of R10,000 a month today will decline in real terms to about R1,700 a month after 30 years - the number of years you could live for in retirement.

This highlights how important it is to plan carefully and ensure that you invest to achieve inflation-beating returns in the long run.

"Inflation is not like a bear market. You don't have minus 20% inflation one year and then plus 20% the next year. It is a persistent and continuous killer over time; a continuous uphill battle.

"It's not like losing in equities which you make back [when the market turns]," Wilson says.

Graham Tucker, the portfolio manager of Old Mutual's MacroSolutions range of balanced funds, says that while inflation is an uphill battle, the hill gets steeper over time. When people delay saving for retirement it becomes impossible to catch up, he says.