I remember, years ago, looking at my storage unit and realizing I kept furniture as transitional objects with emotional baggage. I laughed and asked myself why I couldn't keep a ring or a pen instead of a couch or a recliner!
A long time has passed since then. Decluttering involves more than objects now. It involves how I spend my time, organizations, activities, people, thinking processes, lingering debilitating emotions, routine ways of dealing with food and health issues that don't work for me - or don't work any longer.
The zen koan comes to mind:
Use the raft to cross the river. When you cross the river, leave the raft and walk into the forest."
One challenge is to divest of something that did work for you in the best but is no longer relevant to your life today and now.