Instead, the perfect pillow will support the natural curvature of the spine, making it easy to breathe through the night and wake up ache-free.
You can figure out if yours fits the bill with a simple test from physical therapist and founder of Aletha Health Christine Koth, PT: Lie down on your bed in the sleep position where you spend most of the night. Then, simply gauge if your pillow is making your head hang up, down, or just right in neutral.
Your body structure and the firmness of your mattress will both affect the type of pillow you need. "If you sleep on a firmer-than-average mattress, your body is going to sit a bit higher on that mattress because you can't sink down, and that means your pillow will need to be a bit thicker because your head is sitting higher off the mattress," explains Cary. "Conversely, if you're sleeping on a softer mattress, you're going to sink further down into it so there is going to be less of a difference between your head and the pillow."
Your sleep position will also play a role in your ideal pillow. For example, those who spend the majority of the night sleeping on their side (that's most of us!) will need to account for the width of their shoulders. Your pillow should be the height of the distance from the outer side of your shoulder to your ear. Those with wider shoulders will need a thicker pillow, or even two pillows, to make up the space between their head and the mattress.
Stomach and back sleepers, on the other hand, will usually want to opt for one pillow that's on the flatter side.
And while experts note that the material of your pillow is largely a matter of personal preference, Joshua Park, DPT, physical therapist and founder of MOCEAN, advises avoiding synthetic memory foam pillows that trap heat as you sleep. And Cary notes that feather pillows tend to be a little too soft for the head and neck as you snooze.
All in all, the proper pillow will be firm enough to keep your noggin supported and in line with your spine throughout the night.