There just sounds like there’s such good lore in them, a lot of the old republic era is YA if I’m not mistaken. But it’s for ages 8-14(?) so the quality and content is all over the place.
My brother gave me his old Thrawn trilogy copies when I got back into reading, after those I read the two horror ones, death troopers and red harvest I think, and decided to go deep from the start. He had like 80% of the books found by then.
He buys them used while he travels.