I use this powder every time I use highlighter or when I know I'll end up sweating. This powder helps my makeup last longer and makes my face look less oily! Although the powder looks white and intimidating at first, it blends out into your skin, so don't worry about looking ghostly pale and powdery! It does not aggravate my skin either. Cannot say how long this product would last since it depends on how much and how often one uses it. Would recommend to a friend with oily skin!