I purchased 9 items. Most of them were described as "practically new". A couple of them were described as having "a teeny flaw - a mark that will come out in the wash."
Here's what I found: 1 blouse was faded and missing a snap in front. One of the t-shirts had deodorant stains, smelled of BO and had 2 small, but pretty noticeable holes in the mid-back. There was a jacket that I loved when I tried it on in my dimly lit room - but when I saw it in the light of day - water stains (or something) down the entire right arm, the left breast and left pocket. And the price of the jacket - $137, described as practically new.
So yeah, I have to say. ThredUp is an experiment I won't be trying again.