For instance, the extent to which provisions made for old age will help cover the cost of living in retirement is determined by how the purchasing power of that pension evolves over time. And at the end of the day, purchasing power developments are driven by the real rate of return – that is, the nominal rate of interest with inflation netted out.
So if you are wondering how far your savings will go later in life, a 3% interest rate with inflation at 3% will produce exactly the same outcome as interest rates of zero and no inflation. Inflation here in Germany bounced back recently to a level that is well clear of zero.