For a good year I have been looking for a tough, durable shirt who's primary purpose would be to get dirty, ripped, snagged, etc. It didn't need to have frills, buttons, or fancy plaid pattern. By some chance of luck I saw an advertisement for Carhartt on TV and doing an amazon search, found that they produce more than just tough winter jackets! I saw these shirts for a very decent price and was glad to see 1) they were made of heavy cotton, 2) there is absolutely NO polyester in the shirt (100% cotton), 3) It's a good, plain old workshirt. Polyester makes me sweat like a pig and I hate sweating. Even though it's unavoidable when working under the sun, I'm glad to be wearing this cotton shirt.
One thing I did not like so much about this shirt was that it runs very big. I am a size medium (42.5"chest, 37.5"stomach) and I am 5'8". When I got my mediums, I was swimming in them. I thought it was a joke. But I looked at the sizing chart and I didn't want to risk getting a small and getting something that might be accurate to size. I haven't seen other reviews about sizing, so I don't know if this is just a problem with the mediums or if smalls run large as well. In any case, I took a chance and decided to shrink them in the wash/dryer and they shrunk a little. The shirt still looks a bit large on me, but its nice because It does not restrict movement at all.
I am an animal science student and I work out on animal units/with animals almost everyday. So it is nice to have a couple of shirts designated for rough usage. These have held up well and the quality is surprisingly good.