Fleece, waterproof, water, snacks, headtorch, camera, battery, sticks, map, glasses to read map, first aid, it all adds up. I have an Osprey Stratos 36 which I got as a cheap return, £42. They are around £100 new which is a bit steep. Nice pack, fits me nicely. No big pocket for your jacket though. I do have a smaller 25l which would do for day hikes but it doesn't fit as well so I prefer the bigger one.