Originally Posted by Niloc
As for hydration, I was pretty much just going to bring a bunch of water bottles to the field and in between games drink one, but as I've never played I don't know how long the games are, so would you advise against this? In paintball games are like 20 minutes and you're back to the staging area, however I've heard airsoft games generally go on for much longer. If bringing a bunch of water bottles to the field for in between games works, I'll just do that, but if you think it won't do, I'll get a vertical utility pouch, it can definitely fit 1 water bottle plus it will be useful for any tools I'd need or maybe some food. Or perhaps one of those water bottle carriers.
I'm just gonna step in and say that's a really bad idea: as you seem to already be aware, airsoft isn't like paintball (except maybe for pure skirmishes) and it might be hours before you see the staging area again.
Secondly, notice how I'm starting a new paragraph here to go into another idea: not a giant paragraph, not a second post.
For real secondly, even if you did go back to the staging area every 20 minutes on a hot day in full BDUs with a rig, mags and other gear on, being physically active... 20 minutes is too long. You're better off drinking a small amount every 5-10 minutes than trying to chug a liter every 20-30.
Forget being comfortable in summer: you will be hot. Shirt/BDU jacket, heavy nylon rig, you'll probably have fake ballistic plates (plastic) or soft armor packs (usually closed cell foam) in it, a boonie hat or helmet, plus the weight of the mags, radio, etc. You're putting all this money into trying to get matching MC gear, don't be dumb: put some money into a good 3L hydration system.
There also is such a thing as drinking too much water (http://en.wikipedia.org/wiki/Water_intoxication
) so you'll probably want to get a few packs of electrolyte gel, too (basically like Gatorade in a concentrated gel).
And while expensive, you may also want to pick up a combat shirt to wear under the rig, instead of a BDU coat/shirt. Avoid the knockoffs, the real ones are much cooler (even my TruSpec combat shirts are warmer than my Halys L1 shirt and Crye FROG).
One last thing to consider before you start buying gear: do you want to just get stuff you like, or will you want to put together an impression (i.e., accurately match the look of a real military unit)?