Purchased this for a 2-week-long trip to Germany at the recommendation of my traveling companion.  This backpack was exactly what I needed - large, comfortable, but still conformed to the standard airline luggage size requirements.  It has a lot of pockets for you to keep your things organized and the straps are padded well enough that it doesn't dig into you even when you've got 15 lbs of clothes and other nonsense in it.