Camalback Motherlode or BFG daysack - Very good if you can afford it but if not try and get yourself issued the new 60mm mortar round carrying bag (NSN 8465 99 159 1810) as it is an excellent daysack for all round use. I may be wrong but I believe they are now standard issue for Herrick now too.
If you get a Motherload/BFG, purchase the green/multicam one, not the desert as you will be wearing MTP and it will also do you for when you return on UK exercises/etc, plus we will all be wearing multicam in the UK soon anyway.
Respirator haversack - While it may tell you on your standing orders or packing list for Herrick that you must take your respirator to theatre, I rather suggest you don't. Do however take the respirator haversack, particularly if you are an LMG gunner. Not only does it make a rather effective grab bag for general shit like spare water bottles, FFD's, etc (Nothing that will clank or you wouldn't want to lose) but if you are an LMG gunner you can make all your link into one big long belt and keep it in the haversack. Keep a box on the LMG for initiating fire or breaking contact, then when that runs out, just load the link on from the haversack and blast away till your barrel melts. When your done, break the belt at a convenient length (50-100) for carrying on the gun, tuck the rest back into the haversack and on you go. Rinse, repeat.
Solar charger - If your stationed in a PB, there will be times when you don't have power sockets available. This will come invaluable for charging your iPod, etc. You can't really go wrong with anything from Freeloader or PowerMonkey. And on that note...
Books, iPods, Laptops, etc - Take them. You will need them as the monotony can be terrible even if your a Bastion rat. Netbooks are perfect as they aren't too big and they don't cost as much as bigger laptops but with any laptop prepare for it to get a bit trashed thanks to sand, dust, rough handling, the heat, etc. A padded protective case is a must. I found the best thing for entertaining oneself where books at the end of the day but it depends on how much of a reader you are. If you take a laptop then a most essential item for it is a portable hard drive packed chock full of downloaded TV programs, films, etc.
Don't take an iPad if you have one or where intending to get one. They don't work too well out there because the heat keeps forcing them to shut down.
Spare batteries for your PSP, laptop are something to think about as well if access to power is going to be an issue (If your going to a FOB/PB it's a guarantee at some point it will be an issue at some time)
Crocs sandals - The issued sandals are fine but these will make your feet just that teeny bit comfier as they are a little bit more enclosed so all the dust and small stones don't get on your feet and under your toes. You need a pair of sandals you could, if it came to pass that you needed to, be able to run and fight in (Though if you aren't going to be leaving Bastion then you can probably disregard that).
Socks, underwear and more socks and underwear - Take loads of socks and underwear. If you can "acquire" more pairs of the issued desert socks and underwear then do so as you will go through them a fair bit with all the sweating you will do. If you can't get hold of more pairs of the issued hot weather underwear then try and take sports underwear. You will find anything cotton becomes quite uncomfortable after a while!
Do not bother taking the following things (You won't ever use them)...
Respirator - It's on some units standing orders to take them. Just don't. Save the space.
Issued desert combat vest - A rather pointless item as you will be given a much heavier one when you arrive in theatre. It's called Osprey body armour! Sell it on Ebay! Though DO take the pouches as the new Osprey doesn't come with them.
Your own shades - Just use the dark lenses from the issued protective glasses as your not permitted to wear anything else, not even in Bastion and especially not on the ground. It's a PPE thing... You will see others wearing them but eventually someone with a rank bigger than yours has a go at you so it's not worth the hassle.
Combat jackets - I've never done a winter tour so it might be a different case but certainly for summer tours, you won't wear one of these ever. H13 is going to be a winter tour so seek advice from someone who has done one.
Make sure you take these as some people leave them thinking they won't need them...
Roll mat - Though most FOB's and PB's have cot beds, you will often find yourself sleeping on the floor often throughout your tour. Even if it's just at the airport when your flight has been delayed.
Sweat rags - A most essential item on patrol, you will be grateful for them. There's nothing like the sweat from your forehead dripping down your head and into your eyes, stinging and blinding you when your on patrol.
That's about all I can think of for now. The issued kit these days is actually quite good and I found I only needed small bits and bobs. If I can think of anything else I will add it in a later post or amend this one.
when we got to our PB with had a load of blackhawk knee pads sent forward....they are so much better than the issued ones so hopefully with a good QM you should get them.
As ACAB has said warm kit is a must....i have done two winter tours and it is f&@king frezzing. Also (this may sound odd) but if you can get wellies issued (we did) they can be a god send iN a waterlogged PB!!!!
You get blackhawk kneepads as onthesofa said BUT make sure your proactive in getting one. QM's tend to hoard them up as they are in short supply so they trickle forward very slowly.
Don't worry about pouches. You will be issued a combat vest (Actually called Overvest, Osprey, Assault or something silly like that). It's the most useless thing in the world as why would you want to wear it over your Osprey when you can simply attach the pouches to the Osprey itself. I think it harks back to the days when the body armour we wore did not have MOLLE loops for fitting pouches. Anyway, it comes with all the pouches you will ever need. Just take them.
I'm not too sure about a multicam daysack being standard issue yet. I believe the standard issue daysack now is the desert one I mentioned in my above post. You will also be issued the green NI patrol daysack as well.
Have seen what looks like the insert in a camelback coloured black, fill with water and leave out in the sun for an hour on any down time you might scrabble. Presto limited hot water for a hot wash if you want it. Not sure what they are actually called, will post link if I can find one.
You will be getting pretty much all the pouches you need with the new Mk4 Osprey, which includes LMG, UGL and 7.62 Mag pouches for the sharpshoooters rifle, and all in nifty new MTP pattern too. You'll also be getting a daysack that is much better than the usual old NI patrol sack, but as far as im aware thats in Desert DPM (boo!) If your going to be carring a P226, get yourself a Blackhawk SERPA holster for it, best one Ive come across yet..... As for Kneepads, Altough the issued Blackhawk ones are OK, I much prefer Hatch XTAK's, There smaller, and your knee wont feel as if someone has set fire to it on long patrols, pul it has a super comfy gel inside to it!
Get a serpa with Molle attachment, a camelbak BFM, powermonkey, American ecws smock and a poncho liner, there's not much else you might need to purchase, oh also a softie Sasquatch, that will prob do it.
i was on herrick 11 and i used a Warrior Crusader daysack and it was perfect, dont bother with all them "rig's" or shit, just buy a few mag pouches to put on your body armour, and a big enough pouch for your torniquets and field dressings your gonna want them to hand if ur a combat soldier. where abouts are you going? and with which Reg/Corps.