When was the last time you got a new pillow? Experts say over time, pillows lose their firmness and 'loft' as they flatten, leaving them less comfortable and supportive. There are some ways to tell if it's time to get a new pillow. First, lay a pillow across your arm, if it folds over like a saddle bag, it's time to ditch it. You could also place your pillow on a firm surface and press down in the center, a good pillow will pop back into place once you lift your hand. Sleep experts say your best bet is to choose a medium height pillow that offers support for side sleeping, and the shallowness needed for back sleeping.