Everyone needs, yes needs one of these.
I don't know how I lived for so long without this one- its truly the perfect size. After using it for two seasons, I can say that it's truly one of the most versatile and recommended pieces of gear I own. Love the size, the locking bite valve. Big enough to stuff a light jacket, all my bike tools, a few tubes, protein bars. Awesome to have the larger bladder too- I use it when backpacking, hiking, biking (filling up as much water as I'm going to need). Love it love it love it. You can't go wrong with this one.