The perfect pillow

If you sleep on your back or to the side you need a pillow that feels the gap between shoulder and neck.

If you have a latex or foam mattress that molds to your body you might need a higher pillow.

If you sleep face down you should have low, if no pillow at all. The way to know if it is the right one is that your head should be aligned with the spine.
There are contour pillows to follow your neck\head shape.

Fragrance pillows are personal, you might like it when you fall asleep but irritate you when sleeping.