A blowout can last up to five days, but this would depend on factors like the length, thickness (volume), and texture of your hair.
Pollution, sweat, dust, grime, and humidity are all enemies of blowout treatments and affect how long a blowout treatment lasts. Dust pollution, grease, and dirt all lessen the duration of a blowout.
Touching your hair regularly causes friction which in turn leads to frizz.