Is your OS the latest version? How about your web server? Database server? If not now, when?
A “no” answer to the first three questions is likely not that big a deal. There can be advantages to staying off the bleeding edge. That being said, the last question is the key one. If the answer to that is “I haven’t thought about it”, then there’s potential for problems.
See the full post on the Iasa Global Blog (a re-post, originally written for the old Iasa blog).