SEO is not something that you do for a week or month and get results. It is an ongoing effort and if you do not have knowledge of coding and search engine optimization tactics it can be a difficult road to go down alone. This is where an SEO company can come in and take the work in gaining visibility for the online presence of your hands.
Not everyone needs an SEO expert but if you have a website that needs traffic then hiring an SEO agency can help you achieve this goal by making your site more friendly to search engines as well as end-users.