wear thin vs wear down

wear thin and wear down both are verbs.

Word	Noun	Adjective	Verb	Adverb
wear thin	No	No	Yes	No
wear down	No	No	Yes	No

As verbs, wear thin and wear down are synonyms defined as:

Other synonyms of wear thin include wear, wear off, wear out.

wear thin (verb)	wear down (verb)
deteriorate through use or stress	exhaust or get tired through overuse or great strain or stress
	deteriorate through use or stress