When I reheat leftovers- especially dense foods like lasagna that have fatty (cheesy) outer layers, I find that 30% power-level works best to heat food to the center without burning/​dehydrating the bits on the surface. Otherwise, heating at full power without ruining part of the food leaves the middle cold, leading to a fractured eating session that could be avoided with the extra step and a bit more patience with an extended timer.
When I reheat leftovers- especially dense foods like lasagna that have fatty (cheesy) outer layers, I find that 30% power-level works best to heat food to the center without burning/​dehydrating the bits on the surface. Otherwise, heating at full power without ruining part of the food leaves the middle cold, leading to a fractured eating session that could be avoided with the extra step and a bit more patience with an extended timer.