I usually remember things by very little repetition. When I repeat something too many times I never remember it.
I would assume that people with photographic memories would remember things better. From the very core of our brains, which was near the outside when we were little was easier to remember stuff as the brain was storing it and forming new memory chips on the outer layers. So since our nose can recognize about 50,000 different scents, then it is probably depending on the health of your neurological system right?
People who suffer from neurological disorders often have a harder time remembering many things. Plus we need brain food like healthy greens and proteins in order to duplicate a healthy memory cell, when the others die from possibly traumas or illnesses (like people with cancer, migraines, or frequent fevers).