When you write a page title, you have a chance right at the beginning of the page to tell Google (and other search engines) if this is a spam site or a quality site – such as – have you repeated the keyword four times or only once? I think title tags, like everything else, should probably be as simple as possible, with the keyword once and perhaps a related term if possible.
QUOTE: “For the mostpart it should be fine I think the the tricky part that you need to be careful about is more around doorway pages in the sense that if all of these pages end up with the same business then that can look a lot like a doorway page but like just focusing on the content duplication part that’s something that for the most part is fine what will happen there is will index all of these pages separately because from from a kind of holistic point of view these pages are unique they have unique content on them they might have like chunks of text on them which are duplicated but on their own these pages are unique so we’ll index them separately and in the search results when someone is searching for something generic and we don’t know which of these pages are the best ones we’ll pick one of these pages and show that to the user and filter out the other variations of that that page so for example if someone in Ireland is just looking for dental bridges and you have a bunch of different pages for different kind of clinics that offer the service and probably will pick one of those pages and show those in the search results and filter out the other ones.
QUOTE: “To summarize, a lack of helpful SC may be a reason for a Low quality rating, depending on the purpose of the page and the type of website. We have different standards for small websites which exist to serve their communities versus large websites with a large volume of webpages and content. For some types of “webpages,” such as PDFs and JPEG files, we expect no SC at all.” Google Search Quality Evaluator Guidelines 2017
When would this be useful? If your site has a blog with public commenting turned on, links within those comments could pass your reputation to pages that you may not be comfortable vouching for. Blog comment areas on pages are highly susceptible to comment spam. Nofollowing these user-added links ensures that you're not giving your page's hard-earned reputation to a spammy site.