I have been attempting to update more of my lenses of late and I have seen an increase in traffic and lensrank.
But not until I read CaptainSquid's recent post did I consider more strategically updating my lenses. I highly recommend reading his post, Sneaky Squidoo Lens Label Trick, to learn more about why and when you should update your lenses and how you can help organize your dashboard when you have hundreds of lenses to manage.
For now, I am just updating lenses on my different accounts that are on the edge of tiers. After the beginning of July I will start labeling my lenses into tiers like the Captain is doing to help notice changes in traffic and performance.