I was introduced to this lash primer by my makeup artist and it help me keep my lashes moisturized and looking healthy. my lashes are long so it helps separate them.
I can tell the difference form the days that I use this product before mascara and the days I don't. It seems to help with lash definition and the staying power of the mascara. As well, I think it helps my lashes look longer. I don't use it everyday because it add time to my morning processes but I do use it when I want to look my best.
I received a sample of this maximizer a few years ago and have been using it ever since. It helps lengthen and separate your lashes and usually only need to use one coat of Dior Iconic over the maximizer for great lashes. Both stay put all day till I take off at night.