Hi guys, first post on this forum to back up the fact that wool socks are a gift from God.
I used mine in many different seasons and climates, from summers in Africa to winters in Russia, and I can't get enough of them. Make sure to pack extra pairs. You never have too many socks, as long as you have space for the other gear you need. Dirty socks in a sack or plastic bag in a beanie hat/ushanka will make a great pillow at night. Just close the bag well or it won't be fun for you
Clean socks can have alternate uses if you have "too many" of them: wipe the sweat off your face, blow your nose, whatever.
Oh, and TP. You'll never, EVER have enough toilet paper. Store it somewhere dry, of course. You can use it for thousands of things apart from its original role: wipe cutlery clean and dry after you've washed your mess kit with water, help light a fire, clean your ears, wipe the blood if you got hit from too close...
And there's another very, VERY important thing airsoft wise : bring your extra LiPo batteries in a shock-proof container. You don't want to be near a LiPo that was hit by something hard. If you have flat batteries (as in, their shape is flat, not that they're out of power), a metal cigarette case will do the trick. An original way to carry your LiPos I've heard of is to carry them in a hollowed out magazine, be it a real one or an airsoft one.