This is all up to you of course, but you should use enough that you can smell but maybe not too much where it can overwhelm your surroundings and people around you. You don't want to smell like you've poured a whole bottle of perfume on yourself. It should also be adapted according to the occasion, along with the type of fragrance. Perhaps more on a night out with the girls or on a date and lesser for work. If you are unsure of how much you should be wearing, you can ask a family member or close friend for their opinion!