I’ve gotten into the habit of changing my nail polish once or twice a week, but there was a time when I would wear one color for months and months at a time. My longest run was with this here Rimmel Steel Grey. I don’t even know what made me pick it out the first time, but it’s the only polish I’ve ever actually run out of before it got gunky. I used it up in about 3 months. I bought a new one but that was when my nail polish collection exploded from about 5 colors to easily 25 bottles, but I have a major soft spot for this one.