As I've written about before, I've been thinking a lot about applying data visualization to oft-ignored security problems. A vague notion like "I should be changing my passwords more often" can hang over your mind without actually changing your security habits. Without a firm idea of "which passwords" and "more often," it's likely you won't actually act on these good intentions.
A good visualization turns data into an actionable story. I thought about how to visualize password age, and here's what I came up with:
This is a bullet graph. You can think of it as a series of timelines. On the left, you can see a visual hash for each of your passwords. Each bar shows how many days it's been since you first used that password.
Once a password has been used for over 200 days, its bar turns red. Every time I've used that password on a new site, a black tick marker appears on the timeline. Looks like my oldest passwords are my most frequently used. Uh-oh.
Of course, the data here comes from your browser's password manager. Your passwords may be older than shown here, and you may use them on sites other than the ones it knows about. It's important to establish that this visualization can only show you a "best-case scenario."
That said, if you're like me, and have been using a password for no less than 275 days, you know where you can start improving your security. Now you know!
This add-on is available for Mozilla Firefox. After it's installed, open it by clicking on the small red padlock icon on the add-on bar.