I was just saving the bag from a box of cereal to reuse for vegetable storage, or for shaking meat in flour and breading, and remembering my godmother, who taught me to do this. She was a wonderful old lady and a fantastic cook. She lived in a cluttered (with frilly knickknacks) but neat home. Unfortunately, when she passed, we opened up a door and found that the entire basement, including up the stairs, was entirely filled up to the ceilings with things she had saved "in case"-- furniture, photos, newspaper, old butter wrappers saved for greasing pans, stock certificates from the 1950s. She had grown up during the Great Depression. It took her nephew 3 years to go through everything.
I too own more stuff than makes my spouse comfortable, although in recent years I have been finally getting rid of things a little faster than accumulating them. However, to prevent myself from being like my godmother, I limit the number or volume of things that I save. For instance, I only save 3 cereal bags, and after that number, I have to throw them away. I can save only one newspaper for spreading under messy projects. I keep sentimental cards, letters, photos, etc. in a box and if it is getting full I have to throw some out, instead of starting a new box. I think that helps.