In the course of pruning over 500 books from my personal library over a period of three years (a task completed around 2012), I found the most helpful way of putting things into perspective was to survey all the shelves and stacks and honestly answer what, if anything, each title meant to me. What might I reread if stuck at home for weeks or months due to injury, illness or natural disaster? What were the books that spoke to my heart and, in some small way, could explain to my survivors things about who I am and what was meaningful to me, if I died tomorrow?
Applying that criteria, it was easy to purge things left and right. My fiancee views material objects, especially books and CDs, differently. Even if she hasn't played an album in 15 years (and uses Spotify for 99% of her current listening), she can vividly recall all the ways its third track defined her life during the summer leading up her sophomore year of high school, and it makes objects so alive to her that it's hard to part with them. That's a trait commonly found in hoarders, as described in the book "Stuff: Compulsive Hoarding and the Meaning of Things."
In fairness, she was hardly a hoarder, but after we borrowed "Stuff" from the library she gained more awareness of the fact that the true meaning she assigned to most of her possessions was all in the memories. The presence of a stack of dusty CDs or increasingly worthless DVDs added nothing to her life and only made it feel more cluttered. For her, what has been most helpful is to continually revisit things. In May she was reluctant to get rid of anything, by the fall she was willing to part with a little, and within the last week she's gotten rid of a lot; she just needs time to adjust to the thought of living without possessions she'd previously considered indispensable.