Speaking as both a professional organizer and someone who has lived more than a couple decades, I am a firm believer in letting go of things both physical and emotional which are unnecessary and no longer spark joy in your life (to paraphrase Marie Kondo).
I'm just going to come clean here: I am really loving getting older! No, it's not because I look better than I ever have (it is SO not that, lol); it is because of the perspective and comfort in my own skin which I have gained over the years. I find that as I age, I am finally able to say and do things that would not have been ok when I was even a decade younger. People are less put out by that crazy/outspoken/unstylish/gray-haired old person than they are by a younger person doing or saying the exact same things. I've heard it said that we become our more authentic selves as we age, and I couldn't agree more. As such, I have given myself the latitude to prioritize the things and people which really enrich my life so I can live my life more purposefully. And I highly recommend you try it (or consider it, anyway).
Now, the importance of an uncluttered mind and life cannot be understated -- there is plenty of evidence supporting that. But clutter is more than that stack of papers giving you agita as it grows on your kitchen or dining room table. (Click here for some thoughts on how to address that kind of clutter.) It is in your closets, cabinets, attics and, not unimportantly, also in your personal life. The only way I know to deal with clutter is to tackle it head-on; time-consuming and difficult though it may be. Ultimately, the goal is simply to curate your life so that it is filled with things that actually make you happier and devoid of the things which don't.
People do and hold onto things for any number of reasons -- convenience (I like having this nearby/ at hand should I need or want it), longevity (I've had this for so long, I feel comfortable having it around/ it brings back memories), a potential future need/want (what if I need or will want it sometime in the future), and fear (what if I can't replace it) to name a few. And, only YOU can know what YOU need to keep to make you feel happy and whole. But I assure you that we can all get rid of at least some things which we are holding on to, that, if we gave ourselves permission to let go of, would be good for our personal sense of peace and happiness.
While I think that most folks recognize the importance of sorting and getting rid of the "stuff" they no longer really need in their lives, I also think that most folks don't recognize the importance of curating their personal lives with the same sense of purpose as they do when curating/ culling their physical belongings. For example, think about your friends; really think about them. Do you have any who no longer make you feel good about yourself or your friendship? Are there any who you find yourself asking why you even are friends? I think we can apply some of the same principles to the people in our lives as we do with the "stuff." So, if you cannot figure out why you are still in touch with someone who doesn't seem to care about you/ your life/ your feelings, (or who you don't care about), then perhaps it's time to archive them and find someone (or some people) who will make you feel good about your interpersonal interactions.
A friend recently shared this video on social media. It really hit home with me and made me think long and hard about some old friends and actually even inspired this post. It made me realize that I may be holding on to some people and living some of the personal part of my life somewhat on auto-pilot, which can take up a lot of psychic space if you let it (as I have been known to do). So, I'd like to suggest that you think about the people in your life and decide if they are worthy of all that you bring to the friendship. If some are not, then give yourself permission to archive them (for a little while or for longer).
Getting older has enabled me to see that I don't need to expend time and energy on folks who don't enhance my life anymore. There are, after all, enough personal and familial considerations and stresses without adding ones which are optional to the mix. Life is too short to abide the optional things in your life which cause you anything but happiness, peace, love, and/or joy. Don't you think?!