Google says that the standards on title tag lengths are externally created and not Google recommendations. I have always suspect some element of "myth" about this, but well let's dive into the facts.
How Long Should a Title Tag Be?
Title tags are technically measured in pixels. It’s typically recommended that title tags be from fifty to about seventy characters long.
Those character limits are based on how the titles display on desktop and mobile devices.
Title tags that are longer than what Google displays in the search engine results pages (SERPs) will be shown cut off, which means that nobody will be able to read the full title tag in the SERPs if it’s longer than approximately 70 characters.
Many SEOs and SEO websites recommend a title tag length of approximately 50 to 70 characters because that’s what Google shows in the SERPs.
But that is not anything Google recommends to the SEO community. That 50 to 70 character length for a title is something the SEO community invented as a standard based on what Google is able to display.
But those display limits are based on what a mobile and desktop browsers are able to show.
Title Tag Length Recommendations Are Not for Ranking Purposes
Nobody at Google has ever said that the 40 to 70 character limits are what Google’s ranking algorithms are limited to indexing for ranking purposes.
So it does not make sense to accept the advise for limiting the title tag to 70 characters for ranking purposes when that recommendation is based on what is displayed.
You can search around and you will see that 70 characters is the recommended limit for title tags.
According to Google's Gary Illyes, the Answer is simply No, but with a catch. Gary mentions the need for "tokenizing" (Given a character sequence and a defined document unit, tokenization is the task of chopping it up into pieces, called tokens , perhaps at the same time throwing away certain characters, such as punctuation)
So in summary to keep your mind at ease, though google does not recommend a Title Tag Size, it's important to keep your titles short and concise, not forgeting the meta descriptions. People most times are searching for relevant keywords to their query and do not have time to go through all the details.
Google's approach is more user based than emphasizing on hard recommended limits. So our "myth" has finally been busted.