I love this, and I have some things to add!
Sometimes, for whatever reason, natural fibers won’t be an option for you. For example, winter coats and snowpants: linen won’t keep you warm, cotton holds water and sweat making you cold, and good quality wool outerwear is often prohibitively expensive. Buying synthetic clothing second hand means that you can see how durable the synthetic fabric is, when these fabrics are new it can be hard to tell if corners were cut in manufacturing and if the fabric will last.
For winter wear specifically, some clothing is designed so that the waterproofing can be re-applied when it wears off. This can significantly extend the life of your coat or snowpants.
If you have leather (especially shoes) you need to learn how to take care of it, or it will crack and take in water easily. This is especially important if you live somewhere with cold, dry winters, or if your shoes come in contact with road salt. There are a lot of different ways to do this and each method has its pros and cons, but you usually want something to condition and hydrate the leather (my favourite is Leather Honey) and for shoes, something to seal it, like a polish. Unless you have treated them specifically to withstand water, you should not be getting leather shoes fully wet- if it looks like it will rain, wear something else.
Leather shoes are not all equal, the way that the leather top is attached to the sole determines how repairable a shoe is. Shoes with the sole glued to the leather upper are usually cheaper, and can be great for learning how to take care of leather if you buy them second hand, but the glue will eventually fail. You also can’t usually replace the soles on these shoes. Leather shoes with the upper stitched to the sole can be more repairable, but not always: some stitching requires very specialized machines, and so can’t be fixed by most local cobblers. The Goodyear welt is the gold standard stitching method, and it is generally considered the most repairable, though it is a bit more expensive.
If you’re buying leather new, learn the different types, as the naming isn’t intuitive at all. “Genuine” leather doesn’t mean anything other than that a product is made of real leather, and this is often really low quality. (Usually, full-grain leather is the highest quality, but there’s more to it that I don’t have time to get into)
A solid pair of hand-knit socks can be repaired indefinitey, as long as you stay on top of mending, and imo these are also really easy to mend well. If made of wool, they can also be a lot warmer than other socks.
