Do I need a sitemap?

Yes. Search engines need to see as many of your pages as possible to be be to have them in their index. The more pages of your site in a search engines index, the more chance you have of a user finding your content via a search engine. Sitemaps help search engines to crawl your site properly which could result in an increase in traffic.

A sitemap enables a crawler to view all of your pages and ensure that they are read and stored correctly. If you don't use a sitemap then a crawler has to try and find links to your pages from your website. This isn't always as easy as you'd expect and a sitemap can have a dramatic effect on the way a search engine crawls your site.