I took this on a 4 day trip and managed to cram the following into it:  a pair of pants, 5 pairs of underwear, 5 pairs of socks, a pair of shoes, a quart sized toiletries bag, and some other misc things I needed for travel.  It held up very well and no one on Southwest airlines squawked at the size or if it would fit in the overhead compartment.  I also did not have any issues at the airport when it was scanned by the TSA.  Others have reported issues with the zippers or seams coming apart, but so far I've had no issues.