Nowadays, technology has something new everyday! Previously, you can browse the websites only with laptops or desktops. Today, website can be browsed by multiple devices like smart phones, tablet etc. If website can be used by multiple devices, then your website should be compatible and should run with better view, based on devices.
Is anything applicable to your website, then it NEEDs to be re-design:
Is your website responsive?
Can your website visitors get proper information about your business?
Are your all services properly displayed?
Is your website not attracting visitors anymore?