The scrap saved years ago can find its purpose in a project nobody imagined then.

Keeping things without a plan for them is not always hoarding. A length of fabric, a jar of odd screws, a half used tin: each was saved by someone who could not have named the future use, and some of them turn out to be exactly right five years later. That is a real form of thrift, and it depends on being willing to hold something without a justification.

Keep a small, bounded place for materials with no assigned purpose, and let it be genuinely small. Go through it once a year and use or release. The limit is what stops usefulness turning into weight.