It is hard to let go.
In a better world we would never even buy anything if we are not in dire need of it.
In an ideal world we would not have possesions to begin with, for to possess is to hold on and to hold on is to desire.

Look around. Look at every object you see in your vacinity. And now ask yourself whether or not you have used this object sometime in the last three months. Be honest with yourself, lying will not get you anywhere in this case. Do you really need that planter for those tomato seeds that would turn that neglected window sill into your thriving home garden? Would you have not already started with that if this was so important to you?
Or those scented candles that were only available in a 50-pack?

Maybe you do, or maybe you don't. Maybe you could store them away if you ever need them in the future?
I believe we need to be more radical in the assertion of "do I need this?" and not take "well maybe... also, I like it!" for an answer. Every, and I mean every object in your household should have to fend for itself - give you a reason why it deserves to be called your property. And yes - "this brings me happiness" is a valid reason to keep somethings, especially if makes you think of fond memories or loved ones.
And if you really feel like an object could be of use to you down the line, start using it right now. Otherwise it might not be as important as you thought.

Everything you do not desperately need should be gifted away to friends, family or people in need. Though I cannot lie, I rarely follow this principle myself. But that is what these mini essays are about, isn't it? I am gifting away my thoughts, perhaps not to a family member but to myself in the future, which may also classify as a friend.
I am getting off track.