First impression does matter, especially when prospective customers are visiting your website. Your potential audience will start making assumptions about your business at the first glance of your website. Usually they do not spend more than a few seconds, before they decide if they should stay or leave the site. All the content sould be relevant and to-the-point. Nothing should steal their attention and distract them. Poor navigation or an unattractive user interface, make visitors to leave your website, as much as imcompayibilty with some mobile or tablet devices do. So, if any of these cases apply to your website, and it cannot convert visitors to customers, it may be a good time to consider a website redesign.
The following points can help you to decide what should be improved.