Spare parts

First the mouthpiece wears out because you bite it, and then the valve, which starts leaking or, conversely, stops letting water through. The tube cracks at the bend near the backpack and picks up an odour if it is not cleaned for years. Replacing a spare part is cheaper than a new reservoir and you can do it without tools. Just keep an eye on the tube diameter and the connector type, because these vary across manufacturers and a part from a different series might not fit.