Half-life is the period of time it takes for a substance undergoing decay to decrease by half, and is especially used when talking about radioactive decay.
Many of you redesigning your website right now may be experiencing a half-life of your own, and one that might even be more dangerous (to marketing folks) than a radioactive substance. This half live is the time that it takes for your own happiness with your website to decline by half.
Most marketers and business people get tired of their websites way too fast, and because of this, they redesign their websites way too often.
Your personal opinion of your website's attractiveness has nothing to do with the need for a website redesign.
The goal of your website is to get found by more prospects, and convert more of them into leads and sales. The only person you want to impress with your website is your prospect, and they are much more likely to want to find the information they want than to admire a beautiful flash graphic. A more "beautiful" design or a new design may be more confusing to your prospects, and lower your conversion rate.
Have you suffered from the Website Redesign Half-Life pitfall?