OK, here are some real life numbers. I bought a pair of L 100 speakers for $60. They were in average to nice condition, except one woofer was a cheap replacement. I bought the correct woofer from eBay for $100. Swapped out the woofer, did a real quick steel wool and oil to the cabinets. I listed them on craigslist. They were in average cosmetic condition, not beat up, but not pristine. I sold them to a flipper for $850.
I had another pair of L112 Speakers, that I got in a trade when I bought a Sansui receiver. I didn’t want the speakers, so I listed them on craigslist as well. The cabinets were OK until you looked very closely. I replaced the Grill cloth. One of the woofers was white and one was gray, which was a JBL replacement. I had people beating down my door to buy those speakers. I think I got $1000.
I have a pair of pristine L112 Speakers, that I wouldn’t take $2500 for. To me, they are that good.