1. Coleman 5 Day Cooler: this cooler really does keep ice colder longer than the standard coolers!! I will pack my drinks and anything that needs to be keep cool in this and then cover with as many bags of ice as I can fit. I use the ice in ice boots after XC. I keep a pair of neoprene gloves (you can sometimes find them in the fishing section of sport and camping stores) in my trailer so my hands don't freeze when I'm filling the ice boots.
2. Gatorade powder in my favorite flavors: This is less expensive and keeps better than buying the premade Gatorade. I keep a small funnel with the powder and fill it into 32 ounce water bottles. This gives me the ability to choose whether I want water or Gatorade instead of carrying both types of liquids.
3. Show clothing that wicks moisture: Everything, from underwear to breeches, is more comfortable to wear all day if it has the ability to transfer moisture away from your skin. There are many show shirts available now that can be used in dressage and then converted to a zip neck to wear XC. For breeches, Ariat Olympias are made from Schoeller fabric that is incredibly comfortable. My favorite breeches are the Pikeur Lugana made of the Prestige Micro 2000. The fabric is lightweight and has a silky comfortable feel and fit.
4. Muckers or Bogs boots: Walking XC in the morning dew is guaranteed to get your socks wet if you don't have waterproof footwear. These boots go through puddles and your feet will stay dry and comfortable in wide temperature ranges.
5. SSG Digital Gloves: These are the most comfortable gloves I have ever worn and they wear like iron!
6. Bridle bags lined in fleece: These keep your bridles clean and undamaged during transit. I buy the larger ones which allow me to fit the girth and breastplate/martingale in also. I have everything needed for that particular phase in one place, and I don't have to go searching through a pile of tack to find what I need. If you are staying overnight, it also discourages your horse or the horse next door in stabling from eating your bridles and tack.
7. Rubber rein stops on the top of jumping bats: These help make the bats easier to grip and therefore harder to lose. I recommend dropping the stops in warm water before mounting it on your whip. The warm water makes the rubber a bit more pliable.
8. Magnetic stud dish: So much easier to do studs when you aren't spending most of your time looking through the grass because you knocked over the stud container again! Also stays mounted on the fender of your trailer while you are getting your studs ready. Some people like the wrist mounted version which can be found in some catalogs in the farrier section.
9. Safety Spin Tee Tap: Billed as a safer version of the T tap because if the horse snatches his leg away and steps on the tap, it won't hurt the horse or ruin the tap. It also has the added advantage of being easier to grip, a benefit to those who are older or just really nervous on competition days!
Safety Spin Tee Tap and XC Bat with Rubber Rein Stops:
10.The SOS Strap: Also called a grab strap, this leather hand grip is designed to be attached to the saddle to give the rider "extra insurance" when things don't go quite as planned! I actually prefer to attach mine to the breastplate because it sits in a place one would naturally grab when things go wrong. Straps attached to the saddle sit farther back than I find comfortable. I also prefer an extra long grab strap because you can place it so it sits higher above the horses neck. Perri's Leather makes a longer leather version.