Inflation is an economic phenomenon that can and has been studied and predicted, but this is not a sure shot thing. Which basically means that there is a possibility of inflation hitting the markets suddenly, causing the economic condition to go haywire for a while. This is why, to be on the safer side of things, it is always better to slightly overestimate the retirement income that you will be requiring once you’ve stopped working. Inflation is usually steady in terms of growth, and prices see a surge from one financial year to another. This is why it has a direct impact on your required retirement income.