Most important component of a garment is its fabric. No matter how beautiful the details or how well-crafted the seams are, a garment made from a flimsy, scratchy or pilling fabric is never a good addition to any wardrobe.
When assessing the fabric of a garment you need to look out for two separate things:
- The quality of the fabric itself
- How suitable the fabric is for that particular item
The first point is about figuring out how good the quality of the fabric is compared to other fabrics of that type, whether it is cotton, wool, denim, etc. This should be a pretty objective thing: There are certain properties that distinguish high-quality cottons from low-quality cottons.
The second point is about deciding how well-suited the fabric is (regardless of quality) for that particular item, i.e. for the activities you plan on wearing it for, the weather, etc. Even the highest quality cashmere fabric won't be a good choice for active wear, just like you probably should not pick a delicate silk piece if you are looking for a warm, low-maintenance winter coat.
There are no inherently good or bad fabrics. Every type of fabric has its advantages and disadvantages. The key is to become aware of them, so you can confidently pick the best fabric for the job at hand.
Cotton is a super popular type of fabric for good reason: it's soft, versatile, durable (when high-quality) and comparatively affordable. The most important quality property of cotton is its staple length, i.e. the length of the individual fibres the fabric consists of. Fabric made from long cotton fibres is generally considered to be of a higher quality than fabrics made from shorter fibres.
Linen is made from flax fibres which are naturally smooth but not very elastic. Linen is a great fabric for summer, because it is breathable, dries fast, has a cooling effect, and is lint-resistant. In general, there are fewer quality differences with linen than with cotton and if a garment already has a high linen component that is a good sign.
The quality of denim depends mainly on the quality of the cotton used to create it and how it was woven. Another important property is the stitching on the item. Denim made from high-quality cotton feels soft and even like it's a little moist. Denim should never feel thin and flimsy or so stiff and heavy that you can’t move (unless it is a raw, unwashed piece), but anything in between is fine and a matter of personal choice. If you want to go for a thinner fabric, make sure the yarns are tightly woven and the fabric feels strong and dense, so it won’t tear easily. When you are buying denim second-hand, always check the inner thighs for rubbing. Heavily rubbed thighs is a definite sign that the denim is not the best quality.
Leather is not technically a fabric but a material. The quality of a leather piece mainly depends on what type of “grain” it has. Full-grain leather is generally considered the highest-quality type and refers to leather that has not been sanded, buffed or corrected to retain the skin’s natural fibre strength and durability.