Subdomains or separate domains for separate lines of business?

Question

Search Engine Optimization

There is an old site of an educational organization "pumped" according to regional requests.
Opens two additional directions: children's and remote - we need separate sites right here.
Which is better: implement these sites on subdomains or register separate domains?
One of the sites will contain 80% non-unique content - if it is on a subdomain, will it harm the main domain?
The question is interesting from the point of view of the detrimental effect of the location of individual sites on subdomains of the main site.

Answer 1

Which is better: implement these sites on subdomains or register separate domains?

in general there is no difference, if only customer confidence, but there are little things.
It’s more a question for the client how he will promote these products, maybe he already has beautiful short domains for this

Answer 2

Hey! I have a project in the works, this wholesale souvenirs , there are 15 subdomains, in different regions. I can with 100% certainty that if in different regions, it is better to work with subdomains, yes, there is a lot of time, the content is unique on the main one. Yandex is delighted, positions in the top. Better through a subdomain.

Answer 3

Well, open the seoplan and see how it should be