Recently, a client asked me what about the lifespan of a Web site. I was so happy he broached the subject. Often clients wait to be told when it's time to do a redesign of their Web site.

On average, a Web site should undergo a major redesign every three years. (How long this may seem is indirectly proportional to your budget culpability.) Because the Web changes constantly, users expect something new, different, exciting, and relevant each and every time they get online. Users tire of even their most trusted sites if they aren't occasionally presented with something new.

Redesigns are expensive, of course. It often means completely tearing down the old site and rebuilding it with the same content in a different presentation. It should be much more than that, of course. The new design should reflect the needs and desires of your users, while still promoting your brand in a meaningful way.

The reasons for doing a redesign are more than temporal. A redesign may be called for whenever a serious change happens in your business, organization, or in your goods and services. Here is how to tell if it is time to consider a redesign.

It has been three years since the last one was launched. You should already be working on the next redesign before the last one launched. That's part of the lifecycle. All those great ideas that couldn't be executed the last time should be finding a home before they become stale and irrelevant.

New branding efforts can be an exceptional reason for doing a Web redesign. Users will be presented with new creative from other channels. Your Web site should reflect this. However, less comprehensive marketing efforts shouldn't prompt you to do a redesign. It should be the other way around.

Too much tinkering in the old site can be an indication for the need for a redesign. If you are constantly making updates to the code (I assume you are always making updates to the content), creating new pages that do new things, or revising pages that have been up since the first Clinton administration, then it is probably time for a redesign.

If you change your main navigation then you most certainly should consider a redesign of the entire site. You spent quite a bit of money on the structure of the site the first time around. If you are monkeying with it, then you have come to realize how your visitors need something else. It's time to take a step back and reevaluate how best to address your audience across your whole site.

Your site contains any of the following phrases: "Under Construction", "This site is best experienced using browser XXXX", "Please set your monitor to XXXX resolution", "the Net", "information superhighway", "sign my guestbook", "XXXX hits today!", "Web Page Design by XXXX" or "book your flight on Pan Am".

Recognizing these indicators may help you determine if you should freshen up the place, or tear it down and build anew. Web users are a fickle crowd. It is best not to torque them off.