It is important even before we are born, since it is known that babies develop a bond with their mother through smell. That is why during the first months of life, newborns identify moms through smell. Pure instinct.
Although olfactory memory tends to be romanticised with positive feelings, it can also evoke unpleasant sensations. In fact, certain smells, such as the smell of spoiled food or certain cleaning products, alert us to avoid them. The first time we smell something, it is registered in our brain forever, so that every time we smell it again, it will take us back to that first time. Just as the information we receive from other senses soon disappears from our memory, a smell remains for life.