I have very oily eyelids so all mascaras tend to smudge after a few hours. This mascara is waterproof, smudge proof and stays on my lashes all day long. I have worn this for around 8 hours and my curl was still there and there was no smudging/flaking at all! It is a bit clumpy but that can be solved by wiping the brush before using. However I don't find the 2 different sides have any effect on my lashes.