I bought these to do yard work, so I wanted something sturdy and comfortable. I actually purchased two different styles - these vintage paratrooper fatigues and also the vintage style vietnam fatigues, both made by Rothco and both in the same size.  I got the size that I usually wear, small.  According to the tags in both pairs of pants, size small regular fits waist sizes 27" to 31" with a length from 29 1/2 to 32 1/2.

These paratrooper pants run small.  They fit a lot snugger than the vietnam style fatigues in the same size.  The legs are narrower and fit a lot "closer to the body" than the vietnam style.  The waist size also is smaller and fits tighter, even though the size listed on the tags of both styles is identical.  There are adjustment tabs on the side to adjust waist size.  By way of comparison - the waist on the Vietnam style fatigues fit most comfortably for me with the adjustment tabs cinched about 1/4 of the way on both sides.  These paratrooper fatigues fit best without cinching the tabs at all - and even then they fit slightly tighter than I would like.

According to the tag, these pants are a cotton blend, but they feel like cotton to me.  The fabric is mid-weight and slightly stiff feeling.  They come out of the dryer pretty much wrinkle free. They are reinforced in the knees and seat and have double stitched seams.  They do seem very sturdy. The pockets are roomy and they button closed to prevent things from falling out.  There are ties at the bottom of the legs which you can pull tight to adjust the length and prevent you from stepping on the hem.  (the length on both styles of pants seems to be the same).

Overall, these are nice sturdy pants (keep in mind that they run a little small). For overall comfort, however, I like the Vietnam style better because the fabric is less stiff and the legs are wider and not as snug to the body. The paratrooper style comes in many more colors, however, and they come out of the dryer wrinkle free while the Vietnam style comes out looking a little rumpled.  In the end, I decided to keep both styles, but ended up buying an extra pair of the Vietnam style.