You spend a considerable amount of time resting on them so you should at least make sure you’re using the right kind. Pillows, that is. Experts say to replace a pillow once every two years so that you get your best possible night of sleep. But picking out a pillow often depends on a slew of other factors: your sleeping position, allergies and possibly even orthopedic needs. Don’t lose sleep making your decision - here are four pillows that should fit about every sleeping position and need.