I am often asked how or where we save sentimental objects in our small space. The truth is there isn't a lot of room for sentimentality in a small space. Well I should clarify, there is lots of space for sentimentality and memories but not for the "stuff" related to them. But letting go of things doesn't mean that you lose all of your memories. Your memories, relationships and friendships are yours and the good feelings you get from those relationships are not lost if you recycle a birthday card from a friend. Sure we save a few really special anniversary or major birthday cards and I saved all the cards from the kid's birth. But beyond those pivotal (paper) moments we are quite ruthless with paper clutter.
Any paper that enters our home is recycled unless it is deemed critical. Important papers are put in our mailbox at the front entrance and then sorted and filed when we have time (or the box overflows, whichever comes first). Trevor and I each have one file box that we store any important paperwork, documents or sentimental items. These boxes live in our master closet and we are diligent about not expanding beyond the 2 boxes. We keep things to a minimum by letting go of the physical item whether that means by recycling it or saving a digital copy. We take great advantage of Cloud Drives and USB's to store photos or scans of anything we don't want to forget. I have also taken photos of kid's artwork or a thoughtful card so I can remind myself of it one day without having the physical space taken up. Currently, I store the kid's documents and sentimental items in my file box but will soon need to add another box for them. Yet again, with sentimental items I am quite strict, ultrasound photos, hospital bracelets and a few printed photos and cards are about all I save.
By digitally storing most paper and only hanging onto essentials, we are comfortable in our small space and are busy making memories rather than storing them.