Just how much should you carry and what will you need? The answer is you will need far less than you think, and that is a good thing when you are carrying on your back for 18 to 32 kilometers per day. But almost every pilgrim who sets out is carrying too much when they start. Early on, albergues have tables filled with discarded items that no longer seem necessary after a day or two bearing up under the weight of a pack that is too heavy.
I coached a woman who walked this year. Days before she left we spread out everything she was planning to take. I made suggestions on what she could leave behind. On some things she agreed, on others she reluctantly gave in, and on a few things, like her makeup, she put her foot down. It was her load to carry so who was I to take it away from her.
A week into her journey, I received a message letting me know she had either discarded or mailed ahead, what I had suggested and more, including her makeup.
Be kind to yourself from the start. Whittle down what you think you need before you go.

Here is the list of what I carried in my pack. It weighed about 9 kilograms, or about 20 pounds. This is still too heavy for some people's taste, but it worked for me. The next time I walk I may try to get closer to 7 kg.
Here is what I carried or wore:
Backpack
Waterproof Pack Cover - Integrated into the pack
Sleeping Bag - REI Stuff Sack - Many choose to take only a bag liner, but this was a good choice for me. It was my one luxury.
Clothing
Underwear - 2 pair, quick drying micro fiber
Tee Shirt - Moisture wicking fabric - 1 in pack and 1 on my back
Long Sleeve Shirt - REI Sahara Tech Shirt
Shorts - REI Sahara - 1 pair
Pants - REI Convertable - 1 pair with zip off legs
Sun Hat - REI Sahara
Baseball Camp
Bandanna - Multiple uses
Buff - Sun protection - I honestly did not use this much
Socks - Smatwool PHD Mini Socks - 2 pair in the pack, 1 on my feet
Sock liners - 2 pair in the pack, 1 on my feet
Fleece Jacket - REI - It is an old one I have taken on may treks, I will replace it next time out.
Rain-gear - Frogg Toggs Rain Poncho - Some love ponchos, others rain jackets. I choose the poncho because I had read many accounts of the rain jackets keeping the rain out, but drenching you in sweat. I was happy with my choice.
Sandals - Teva's Terra Fi Lite Sandal - light, comfortable, and could be used to walk in if needed.
Knee Brace - I have an old ACL injury and brought it just in case. I ended up using it more than I thought I would.
Hikign shoes - New Balance MT1210 - I will talk about selecting the right shoe in another post, but for now, these served me well. I added New Balance's motion control insert. Together they were both comfortable and supportive.
Gear
Headlamp - Petzl LED - I used some morings, a a few times in the albergues after lights out. I could have done without it if I had too, especially if I had a key chain LED light.
Watch - Very helpful for judging distance and pace.
Trekking Poles - REI Traverse - A must have in my mind.
Nalgean Water Bottle
Cellphone - Iphone - I never did get a sim card. I found wifi everywhere and used it to make Skype to make calls, update Facebook, as my media player, and web browser
Camera
Mini Tripod
Power cords and chargers - For camera and cell phone
Money Belt/Wallet
Guide Book
Journal
Pilgrim's Passport - I picked this up at the office in St. Jean
Stuff Sack - Sea to Summit Lightweight Dry Sack - 4 Liter (2) and 8 Liter (1)
Small Hiking Towel =
Safety Pins - To keep laundry attached to the line.
Paracord - A 10 ft. length to use for a cloths line, if I needed to hang them to dry indoors, or for lashing things to my pack. I never used it.
Repair kit - Thread, needles, and a bit of duct tape
Rock - Taken from a beach at home to leave at Cruz de Ferro
Personal Care
Sun Glasses
Sun Screen
Ear Plugs
First Aid Kit - Band-Aids, Neosporin, Ibuprofen, Moleskine, ACE Bandage, and the like
Razor
Brush - I cut the handle off to save weight
Tooth Brush and Tooth Paste
Deorderant
Bar of soap which could be used to shower and to wash cloths.
Vaseline - Coated feet with is before putting on socks to prevent blisters
The women I traveled with also brought a scarf that they could used in various ways as an accessory. This also came in handy to cover their shoulders when they visited a church or cathedral. Several also brought a short dress, which they wore in the afternoons and evenings. The comfort and how it made them feel to get out of their walking cloths made the extra weight worth it to them.
Several suggestions as you pack:
Be fitted for your pack by a professional at an outfitter, like REI
Start assembling your gear early
Borrow what you can
Take advantage of sales and seasonal closeouts
Walk in the cloths you think you will take to make sure they are comfortable
Practice packing your gear into your pack
Leave plastic bags at home, the people in the albergues will thank you
Always be asking, do I really need this
Much of the extra weight people carry is out of fear. What if (fill in the blank) happens, I will need or want this. You can pick up just about any thing you might need along the way. Only carry what you know you will be using, and trust you will find what you need if something comes up. Even if you cannot purchases it, the chances are another pilgrim will be able to share.
They say the Camino provides. Allow yourself the opportunity to experience this wonderful truth, but not carrying something for every contingency.
The stories which result from your willingness to trust will be some of the one you will end up sharing the most when you get home.