Honestly speaking, there is no specific time when you should consider redesigning your business website. However, to chalk it down, I suggest to consider it whenever there are brand-level changes occurring within your brands. Brand-level changes could be the launch of a new brand, or change in the color or packaging or an existing one. It might also be an introduction of a new variant in the product line, or if your business is declining and there are newer trends in the market and your website is clearly declining those trends, then it is time to consider a new design for your business website.
If you are considering to combine a new look with new functionalities, make sure to question yourself about the meeting of your targeted goal through the said strategy and its likelihood. Global businesses do not always want to redesign their main websites if the change that is going to happen is very drastic for the customers. In such cases when the owners are just not sure about the outputs, a slight tweak in the design is suggested, instead of a complete re-do that might involve significant cost and labor in it.
Content Strategist at Branex