Do you reapply during the day? If so what and how?

Do you normally reapply your perfume during the day?

If so, do you always bring with you the specific perfume you chose in the morning or do you just have another one that you carry and you reply that one instead?

Do you buy a separate travel size one? Or do you just carry the full size bottle with you?

Also do you wait until your fragrance is like basically fully faded?