But for some people it is very difficult to let go of old things or they are simply so unorganized, that it seems to them like an unbearable task to start sorting out things, which are really not or no more necessary and which only rob energy just by lying around in certain corners.

What and how to "Declutter"?
Start with asking you some questions: Do I love this item? Have I used it in the past year? Do I have another one that is better? Should I really keep two? Do I really have the energy and time to repair this item for reuse? Does it have sentimental value that causes me to love it? Or does it give me guilt and make me sad when I see this item?
Feng-Shui-wise it is advisable to throw away all crockery, which is chipped or cracked even only tiny parts, as eating and serving from of broken cups and plates can bring bad luck and cheating and money loss in business. It symbolizes "it cuts the mouth" and literally affects your speech so that what you speak can get you into trouble.

Cleanse out everything that does not make you SMILE!!! If you cleared out and made room, then you have enough new space to display your valued objects in an adequate place and can enjoy them, whenever you look at them.
This way you can live every day with the peace of mind that results from having your home exactly the way you want it and where you are in control of your stuff, and not the other way around.