It depends of the concentration of the fragrance oil present in the fragrance, a perfume with a higher concentration typically lasts longer than one without; as well as the type of fragrance - citrus colognes consisting of mostly top notes would not be as long-lasting as oriental fragrances which contain more base notes like woods, amber and vanilla. There are other factors that play a role in the longevity of a perfume as well, like the humidity as well as the state of your skin - dry skin is less likely to hold on to fragrances.
A Waft perfume will last you about 6 to 8 hours or even longer.
