I posted this on Harajuju, but I'll post it here too:
One thing that's important to discuss is that quality is not always correlative with durability. Quality is a difficult thing to define and I think it's going to differ from person to person. For example, I think we can all agree that fast-fashion clothing is bad quality, but how do we define something that is
good quality? Is something like a very thin silk low quality simply because it is not durable?
Quality, for me, can generally be traced to either two things, depending on the type of material.
1. For "natural" materials, such as leather, is it high enough quality that treatments haven't been applied to mask its poor appearance? Does it have the traits which we would generally desire, such as the appearance of a real flesh, thickness, a lack of crinkling?
2. For processed materials, like woven fabrics, coated/treated fabrics, synthetic materials, does the processing show a high level of care and attention to detail? Is the end result visually beautiful under close inspection? For materials from which we
can expect some level of durability, have measures been taken to ensure the maximum durability?
And then there are things that we can measure more easily, such as the quality of the stitching, symmetry, etc. But even then, sometimes we can lose things like symmetry depending on the way the item was constructed. Hand-made items often have more "imperfections", but are they lower quality?
Buying clothes that will last for a long time based on durability is a mistake, IMO. Inevitably, even the highest quality clothing are prone to defects or accidents. Some defects simply aren't acceptable (for example, my co-worker's Rick Owens boots had a peeling sole after just a month of wear), but things like stitching ripping along the seam, or small holes/tears just happen – that's the nature of something that you wear on your body every day.
When I buy something for its quality, it's not so that it will look the same five years from now as the day I bought it. Even if I think that would be nice, it's not realistic. I buy it for a quality material that looks nice now and will age well, and I buy it for the quality of its
design. Quality and design are not separate concepts as your post seems to indicate. Lets take these Carol Christian Poell boots, for example (no particular reason for this example except I saw them recently and I like them):

If you took this
exact same design and used low quality leather and treatments, the value of the shoe would be entirely absent. Because the beauty of it stems from the combination of high quality materials and good design. The material is a part of the design. The quality and the design are inseparable because they are one in the same.