Teddy: Since your post seemed to indicate you want to perfect your English, "which inevitable causes some problems" ought to be "which inevitably causes some problems". You are modifying the verb "causes", which requires an adverb and the adverb ending -ly, not the adjective form.

On leather: I have the sleeveless torso of a tan, lambswool-lined leather jacket. Not enough left to refashion into a jacket per se, but maybe a Conan-esque fur vest is doable. This time, when I sew it, I will use a zigzag stitch and maybe seam tape to stabilize the old and weakening leather--the slippers (made from the sleeves of said jacket) are already falling to pieces along the seams and they're not so old even if the leather itself might be.

That and I have no interest in sewing the necessary new sheets and duvet cover, even if the guest bed needs them in two weeks or less, before the guest arrives. Straight lines are so boring.