My Camino packing list has been basically unchanged for the last decade. But this year, after reading the words of wisdom of iconic posters like sil, mspath, and anniesantiago, I decided to buy an immersible electric coil (plus plug adaptor) and a tin cup to bring on the Camino. I also brought a plastic baggie filled with instant coffee and in Spain bought a tube of condensed milk. I don't take sugar in my coffee usually, but I can't drink black coffee, so the condensed milk was the more palatable alternative. Altogether it probably weighed 500-800 g, so this was a considerable addition to the pack. But I had had too many coffee-free mornings on the Camino Vadiniense, Invierno, etc, and was looking for a solution.
I can't tell you how many times I thanked Sil, mspath and Annie for the tip. If you're in an albergue with a kitchen, you won't need it, but the caminos I've walked lately don't have a whole lot of those. Of the 44 days of my last camino, the Levante from Valencia, I'll bet I used it more than 35 mornings. I will never walk again without it, thank you thank you thank you!