This can be because you are turning your waver heat up too high. When you use a higher heat (e.g. 210 °C) on the hair to wave or curl it, the cuticle can slam shut and flatten so much that it won’t hold a bend. A super-flat cuticle works well when you want shiny, sleek strands, but not so much when you want texture. Using a lower temperature (e.g. 180°C) will create a longer-lasting bend. In saying that, if your wave or curl drops out within a minute or two of waving/curling your hair, you probably need to dial up the heat.