4 years in normal use - Full damage.
After just over four years of normal use of my duvet cover (no tumble drying, no unusual wear or stress), I experienced extensive material deterioration, with the fabric disintegrating across an entire side.
My complaint was rejected and justified with points such as a superficial stain, the packaging used for shipping (a new standard cardboard box), and an unsubstantiated assumption of improper care — despite this demonstrably not being the case. In particular, excessive heat during tumble drying was cited as a likely cause, although I never use a tumble dryer.
None of these arguments have a factual connection to the actual damage. For a high-end brand like Schlossberg, both this assessment and the way I was treated as a customer are, in my view, inappropriate and disappointing. As a result, I will consider other manufacturers in the future.