Question

1. Don't throw away your old clothes, shoes, or books.
They will be useful to someone.
2. You can buy things at low prices.
3. Don't throw away your old clothes, your old shoes, or your old books.
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Q1: Are "your old clothes, shoes, or books" in generic use?
Or are they just mean some of "your old clothes, shoes, or books" or many of "your old clothes, shoes, or books"?
Q2: In #2, is the word 'things' in generic use? Or does things just mean some things?
Q3: Does #1 always mean #3?

Answer 1

Q1 - yes, "your clothes, shoes, or books" means all of them, not just a few or some of them.
Q2 - "things" means material goods generally, nothing specific (not some, but all).
Q3 - yes, one and three mean the same. Repeating "your" before each item in the series is not necessary, though. Number one is best.