How many winters should a good wool coat give you before it looks tired?

I want to gently disagree with the premise that price predicts lifespan. In my experience the variable that actually determines how long a coat lasts is maintenance, and it is almost free. Brush it after wear, hang it on a broad shouldered hanger rather than a wire one, get it cleaned once at the end of the season rather than repeatedly through it, and deal with moths seriously. I have had a mid priced coat outlive an expensive one purely because I looked after the cheap one and shoved the expensive one in a wardrobe wet.

I keep a note in my phone of what I paid and when I bought things, mostly because I was curious about exactly this. Coats have been my best category by a distance. My daily winter coat is in its ninth season and still looks respectable, and the one before it went eleven years before the lining went and I had that replaced rather than replacing the coat.

Boots are the second best if you buy something resoleable and actually get it resoled. Mine have had two resoles and the uppers are better looking now than when they were new. Jeans are the worst by a mile, four seasons at most before the thigh goes, regardless of what I paid. Knitwear varies enormously and depends far more on fibre and knit density than on price.

Read the composition label and the construction rather than the price, because the two are only loosely related. On a coat I want a high wool content with as little of the cheap synthetics as possible, a proper lining, and seams that are sewn rather than fused. Fused construction is what makes a coat bubble across the chest after two seasons and there is no fixing it. I have owned a genuinely expensive coat that was fused and a mid priced one that was not, and the mid priced one is still going while the expensive one went to a charity shop looking lumpy.

Wool coat, eight to ten winters if you brush it and store it properly. Jeans, three or four. Boots, effectively indefinite if resoleable. Knitwear, depends entirely on the yarn.

Ask whether the thing is repairable before you ask how long it lasts, because those turn out to be nearly the same question. A coat with a replaceable lining, boots with a stitched sole, a knit in a plain enough yarn that you can darn it. Everything glued or bonded has a hard stop, and everything sewn has a long tail.

I dry cleaned a wool coat roughly monthly for two winters because I wanted it to look sharp, and I effectively sanded the face of the cloth off. It went from a soft matte finish to a shiny flattened look, particularly on the seat and the forearms, and no amount of anything brings that back. A good brush and airing after wear, spot cleaning, and one clean at season end is what I do now, and my current coat looks better at four years than that one did at two.