Having walked, now, two different Caminos, and having blisters and foot issues on each, I’ve learned a few things…
From my experience, the factors that make a difference are (1) weight carried, (2) footwear, (3) practices while walking.
Weight Carried: Pack Light… I’ll be posting a list of the contents of my pack after the camino… During the camino, I had to reduce the weight I was carrying… General guidelines for maximum weight: 10% of your body weight…
As a side note: BOOTS are usually much heavier than TRAIL RUNNING SHOES!
Footwear: On each of the Caminos that I’ve walked, I started out wearing boots… regular hiking boots… Hmmm… well, FEET SWEAT! and both heat and moisture build up in the boots… increasing the possibility of blisters… On my recent camino, I went to six different sporting goods stores in Salamanca to buy TRAIL RUNNING SHOES… In Spain, people are smaller than I am… the maximum size that stores carry is 48… I wear a 49 or 50, depending on the shoe manufacturer… Well, TRAIL RUNNING SHOES breath better, release the heat, and even if they get wet from rain, dry quickly… especially if you stuff newspaper in them overnight… When I walk my next camino (Probably the Camino Del Norte!), I will only wear TRAIL RUNNING SHOES!
Practices while walking: subtext: SOCKS! I carry two pairs of socks for each day… and it is important to stop for a break for you feet occasionally! So, take the shoes off… and the socks off… cool your feet down… and CHANGE SOCKS! Although Clean socks are desired, what is most important: DRY SOCKS… even DIRTY DRY SOCKS… will always be better than moist or socks!
Also, subtext: IF YOU FEEL ANY PAIN while walking: especially HOT SPOTS, stop and deal with your feet! If you are feeling any pain, it is important to deal with it immediately because not dealing with the pain will only make the issues worse!
I also like this book: FIXING YOUR FEET by John Vonhof (It’s in its 5th edition as of 2011!