I used to collect D&D rule books from the different editions, but lost interest with 3e (I own a copy of the 3e PHB and that's all, and never even got to 3.5), the game had lost the "spirit" of the original, and therefore lost me.
I used to have a huge collection of D&D and FRP materials. Then I got married for the first time in my mid-40s to a woman marrying for the first time in her early 40s. We both had a complete house worth of possessions to merge into one normal-sized house. My entire room packed full of gaming materials had to be cut WAY back. I now have PDFs of most of the old adventures I really want and a much trimmed down collection real rulebooks.