When you think of letting go of things when they are no longer useful or give you a spark of joy, especially sentimental things, remember that all of your past experiences are already woven into the fabric of your Being. If you were to suddenly leave your home and all of your possessions, taking nothing with you, the life that you have lived, for better or for ill, will go with you even though your hands are empty.
There are things we possess that trigger special feelings, even as when you hear a particular song or smell something unique from your past. These sensory cues will bring back a flood of memories and emotions. It is not that the memories are stored in an item, what is heard or smelled; rather those cues bring forward the memory into the conscious mind, a memory that was always there but residing in subconscious layers of the mind.
The belief that persons or objects are the repository of any particular feeling or thought leads to an attachment that blinds you to an inner reality that whatever you experience already resides within you. Vividly recall any person, place or thing from your past and you will experience all the powerful feelings from that time. Then imagine that situation is no more, and then you feel a great and sudden loss. Now imagine that the emotion you experience when you think of a person or place is and has always been within you. When you met someone or visited some place you may have had feelings that surfaced for the first time, but in reality those feelings had always been with you.
And this is the moral of the story, the story of your existence; all that you treasure, all that you hold dear is right within you, within your heart, mind and soul. And even if the instruments of body and mind were to become broken or destroyed, your Soul, the repository of your entire existence will forever know those experiences. The love you have experienced, the joy you have known, the security that made you feel whole, all of that and more are elements of who you really are and have always been.
And that is why attachment to things, persons or the past makes you feel miserable, because you come to believe that you are bereft of those qualities once those conditions have past. This is an illusion, a wave of the wand of Maya, the delusive force of separateness. In God-consciousness you reclaim all that you truly are, and it is all good. Do not be afraid to let go of those things that tie you to past experiences when it is time to let them go; affirm that you always have them with you, all of that and much, much more.