We get it, the word "audit" isn't an exciting term but a design audit is something completely different, it saves companies from their visual style and communication getting lost which could see a downward spiral in the branding, positioning, and inevitably sales.
"Why is that?" you might be asking, well it's because users don't like inconsistencies. It's annoying if a brand keeps changing or isn't cohesive. No one wants to deal with things that annoy them. Have you ever browsed a website to purchase something, and the different uses in colour, the layout of the website, or too many glaring typos or grammatical mistakes made you question the validity of the website, brand, and the company which prevented you from making a purchase? That's why a design audit is so important because it finds these inconsistencies and rectifies them.
Design audits are there to help a brand or a company express itself consistently across all channels. This includes not just visual channels but the messaging and verbal or written communications too. A design audit includes all aspects of the brand which is not just the visuals to make sure consistency is adhered to. Think of a design audit as a brand checkup.
You should carry out a design audit when there hasn't been a style guide implemented or adhered to for the duration of your brand or company, or when you notice a lot is going on and you haven't been able to focus on your brand as much so there might have been a few inconsistencies that slipped through the cracks. Noticing this isn't anything to be ashamed of at all, by getting on top of it now means that your company or brand is levelling up and you care enough to keep it on the right track.