To help explain the different strengths in a mens fragrance the following is a general rule, depending on your skin type.

Eau de Toilette or EDT         6-8 hours
Eau de Cologne or EDC        2-3 hours
Aftershave                          4-6 hours
Aftershave Balm                  6-8 hours

The above strengths are only a guideline because skin types and the ‘layering’ of product (eg body lotion and deodorant etc), will differ from person to person.