That's one of the great things about UF, there's always something new to discover. I've read through the whole saga 3-4 times now and SoS even more than that. Every time I do, I'll catch a reference I missed the first time around or I'll have been exposed to the source material since the last time I read it and a minor character, off-hand reference, or setting will suddenly jump out at me as strikingly familiar.