If I go trekking I pack as little as possible, but all I need , in my backpack. My backpack has between 17 and 20 kilos , water for one day included . I have a packing list ,so that I forgot nothing. It is so a lot of things from the first aid to sleeping bag,sleeping mat , headtorch, rainwear..... I going to go from the North point of Austria to the South point of Austria this year. That are 550 km and 18000 m altitude. I would like going the tour in 19 days.