1. Pretty much goggles are needed, make sure they're ANSI Z87.1. Helmets are, yes, for looks. I wear a brown triangle bandage as a do-rag. theres a pic in my personal gallery. Just make sure its comfortable.
2. Leaving the field is not actually despised, but try to do so at a convenient opportunity. I had to go off-field during an engagement, because my gun killed itself.
3. Dont worry about NVGs, we wont be out that long. Might as well bring dope and beer.

I keep a flashlight handy, AA maglite on a lanyard, tied to my pants. If I lose my pants, I've got other issues.
4. I usually throw about 10 dollars worth of Tigers Milk bars in my buttpack (thats alot), and an MRE or other portable lunch. the excessive quantity of TM bars is incase someone else needs one. I did throw one at somebody at G18 last year. Have something worthwhile in the car, but always have some extra food on you. I also carry a 3-litre camelbak, and an extra 1litre nalgene. the LRRP-style rig i'm still building includes an MSR Sweetwater, but all the long-duration ops keep coming up short. Dont worry about it. Keep a couple extra bottles in the car.
5. I prefer to carry somewhere in the neighborhood of 800 - 1200 rounds, but i'm a bit over-cautious. some guys carry as little as 400. As much as you can carry, would be the safest bet. I also keep a 100rnd speedloader on my buttpack, just in case. If this is your first big op, just bring alot of ammo. I carried 1000 in my first big op, and I reloaded.
6. I try to carry atleast one spare battery, and again, I'm overcautious. my current loadout has me carrying only 800 rounds, but two 2000mAh batteries. Have both charged, and keep the spare one on you. I also have a charger that will hook up to a car battery, just in case. I like it, I like it alot.
The King Of al-Talk. Hey, at least I'm not a troll.
My dog wouldn't know what to do with a duck if she caught it, but she's cute. And hates Mexicans. +1!