A lot of people wonder how long it takes to get a new site indexed and ranked, but people do not often consider the flip side. Namely, how do you keep an old site fresh in Google's eyes. Of course, lots of old sites rank just fine. In fact, some old sites are low quality and still rank well through sheer number of backlinks pointed at them. However, some old sites are watching in agony as brand new sites come along and usurp their decades long ranking throne in just a few short months. How do you keep this from happening to your old site that's been around the block a few times? Matt Cutts answers the question in this week's Google Webmaster Tools video.
Essentially, the answer is not to coast or rest on your laurels, however nice and cushy they may be. This is especially true if you are in an industry that is always evolving (like search engine optimization for example) or even an industry that overhauls itself every few years. If you are number one in the rankings but you don't add to your lead, new sites will come along, churning out page after page of content, and before you know it, they have you beat. To keep up, you should NEVER STOP PRODUCING NEW CONTENT, no matter how comfortable your lead is.
The other aspect to consider is design. If your site is ten years old, it may look like its ten years old. Just like kids today scoff at the effects we thought were so cool in movies of the 80's, the average internet user instinctively can tell if a site was designed in the 90's or even in the early 2000's. Just like clothing styles evolve over time, so do websites. So if you want to stay competitive, you need to make sure your website keeps up with the times.