When putting away money for retirement, consider inflation-resistant investments. The past 3 years really fucked some of my friends who didn't heed that advice.
I believe they're talking about investments that share that chsracteristic. Generally Bonds and CDs would probably not be examples of good inflation resistant investments. in general, I believe index funds and I bonds are more resilient to inflation.
Better still is maintaining diverse investment types.
I'm open to corrections