Some page titles do better with a call to action – a call to action which reflects exactly a searcher’s intent (e.g. to learn something, or buy something, or hire something. THINK CAREFULLY before auto-generating keyword phrase footprints across a site using boiler-plating and article spinning techniques. Remember this is your hook in search engines, if Google chooses to use your page title in its search snippet, and there is a lot of competing pages out there in 2019.

Google will INDEX perhaps 1000s of characters in a title… but I don’t think anyone knows exactly how many characters or words Google will count AS a TITLE TAG when determining RELEVANCE OF A DOCUMENT for ranking purposes. It is a very hard thing to try to isolate accurately with all the testing and obfuscation Google uses to hide it’s ‘secret sauce’. I have had ranking success with longer titles – much longer titles. Google certainly reads ALL the words in your page title (unless you are spamming it silly, of course).
When using the Keyword Explorer, Ahrefs will also produce the "parent topic" of the keyword you looked up, as you can see in the screenshot above, underneath the Keyword Difficulty meter. A keyword's parent topic is a broader keyword with higher search volume than your intended keyword, but likely has the same audience and ranking potential -- giving you more a valuable SEO opportunity when optimizing a particular blog post or webpage.