There's a whole list of documents you probably have that are outdated or expire at some point. Some are easy to forget about if you don't use them very often, like your passport. My passport expired about four months before I was going to go to Canada for a weekend. I realized this too late and had to cancel that trip. So I had to renew it, which was easy enough, I just couldn't go to Canada when I originally wanted. Take a few minutes and go see when the expiration date on your passport is. If it's soonish, you might want to start thinking about renewing it, just so you have it and don't have to think about it for a while.
Your license. My best friend didn't realize that her license expired on her 21st birthday. I feel like most people know this.
Your resume. I can't stress how nice it is to have a finished resume before you actually need it. Then all you have to do is attach it and you're set. It's so great to just attach it. So go work on your resume and get it perfected. You'll appreciate it later. I promise.
It saves a lot of worry and panic if you keep up on these things.
Is there anything else you can think of that you should keep updated?