When my clients are feeling indecisive about whether to keep or toss something, I ask them, "If you were in a store today and you were looking at this, would you buy it?" This allows them to feel the immediacy of whether they really care about something or not.
When we surround ourselves with things that don't matter to us in the moment, we perpetuate a stagnant environment. This creates a dullness in awareness. Our clarity is diminished. We can feel sluggish in our sense of self. When our most important asset, our ability to think clearly is harmed, it's time to let go of those things that don't serve us in our lives now.
Take a tour of the things in your home. Walk around as if you were in a store. What would you buy today? What wouldn't you purchase? Today is a great day to let go of those things you wouldn't buy. You gain so much by letting them go.