Why is a page title tag important?
A page title allows the reader to distinguish the pages from one another. By inserting a powerful and descriptive title, the visitor can scan a website quickly to see what it's about, and then decide whether it's interesting to read further. Clearly specifying a page title can also ensure that the website receives a higher ranking in the search engine results.
In order to optimally display a title in the search engines it's recommended to limit the title to 65 characters, so the title isn't cut off in the SERP, the search engine results page.