The last time I looked Google displayed as many characters as it can fit into a block element that’s about 600px wide and doesn’t exceed 1 line of text (on desktop). So – THERE IS NO BEST PRACTICE AMOUNT OF CHARACTERS any SEO could lay down as exact best practice to GUARANTEE a title will display, in full in Google, at least, as the search snippet title, on every device. Ultimately – only the characters and words you use will determine if your entire page title will be seen in a Google search snippet.
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 2020.
OBSERVATION – You can have the content and the links – but if your site falls short on even a single user satisfaction signal (even if it is picked up by the algorithm, and not a human reviewer) then your rankings for particular terms could collapse – OR – rankings can be held back – IF Google thinks your organisation, with its resources, or ‘reputation, should be delivering a better user experience to users.
QUOTE: “Cleaning up these kinds of link issue can take considerable time to be reflected by our algorithms (we don’t have a specific time in mind, but the mentioned 6-12 months is probably on the safe side). In general, you won’t see a jump up in rankings afterwards because our algorithms attempt to ignore the links already, but it makes it easier for us to trust the site later on.” John Mueller, Google, 2018
There are a lot of definitions of SEO (spelled Search engine optimisation in the UK, Australia and New Zealand, or search engine optimization in the United States and Canada) but organic SEO in 2020 is still mostly about getting free traffic from Google, the most popular search engine in the world (and almost the only game in town in the UK in 2020):
Advertising with Google won't have any effect on your site's presence in our search results. Google never accepts money to include or rank sites in our search results, and it costs nothing to appear in our organic search results. Free resources such as Search Console, the official Webmaster Central blog, and our discussion forum can provide you with a great deal of information about how to optimize your site for organic search.