CarharttMen's Loose Fit Midweight Logo Sleeve Graphic Sweatshirt

Q: i am 5'8 and 145 lbs. would a small or a medium work best?

I'd get a medium one buddy..I'm 5'8 191..large fits me perfic

Q: What’s the longevity like?

This quality is not what you'd expect from Carhartt. See my review with pictures. 4th time I wore it & it's already 'pilling' up in numerous places. Thinner than my other Carhartt Sweatshirts. After only 4 times wearing looks more like Old Navy quality (no offense) but I could've bout 3 for the price of this one.