It can of course vary considerably by store, and I’ll happily spend time in both but, generally:
Second hand bookshops are curated actively - like, they’ll only stock desirable books. They’re owned and run, usually, by people who love books. The staff tend to be knowledgeable.
Charity book shops are much less curated - to the extent that some just stock whatever is donated (which, of course, is largely made up of books people don’t want), so they tend to have a large collection of random books of not as high quality. They’re run by volunteers - which generally means enthusiastic staff, but it does not mean knowledge about books.
1000% yes, at least with the help of book scouts that cull #2 and sell what they find to #1 for ~40% of retail.
If you want a fun fictional take on this, John Dunning's Booked to Die is a biblio-mystery about a Denver detective / book-lover investigating the murder of a book scout within the 1980's Denver used bookstore scene.
If you’re in the uk, I think you’d understand the question.
Charity shops have sprung up all over on high streets, even while businesses around them fall. It’s not hard to imagine that the economics are different and that non-charity shops can’t compete due to lack of special tax treatment.
Second hand bookshops are curated actively - like, they’ll only stock desirable books. They’re owned and run, usually, by people who love books. The staff tend to be knowledgeable.
Charity book shops are much less curated - to the extent that some just stock whatever is donated (which, of course, is largely made up of books people don’t want), so they tend to have a large collection of random books of not as high quality. They’re run by volunteers - which generally means enthusiastic staff, but it does not mean knowledge about books.