It depends. If your website was built within the last 3 years, you are probably safe. However, if your website is 3 years or older, you may need an update.
Newer technology and design principles make newly-built websites more user-friendly and perform better in search. Older sites may not look as great or perform as well on all screens, leading to poor user experience and lost leads.
For more advice on how to tell if you have an outdated website, read our article: 7 Warning Signs Your Website Needs To Be Updated.