I used this backpack for a 7 day trip to Washington D.C. in March 2018. It held three sweaters, 4 shirts, two pairs of thick long underwear, 7 pairs of wool socks, 7 pairs of underwear, three pairs of pants, sketchers, gloves, two hats, a bulky scarf, a quart size bag of toiletries, and a book.  It was stuffed but still eligible to carry-on for United Airlines.

Unfortunately, the packed bag was heavy and uncomfortable to carry.  The purpose of this backpack is to maximize your carry-on, not comfort.