Not necessarily. If you live in an area where its really dry (~ 20% RH or less), some will leave moist hides in the viv all the time.
Most areas, with Pennsylvania included, the humidity levels are just fine. Corns are really tolerant of varying degrees of humidity. If you find your corn is having trouble shedding (incomplete), you'd either want to give them a moist hide when they go blue, or mist the cage. If you have a large enough water bowl in a tank, covering part of the screen lid with a towel or saran wrap will also help keep the humidity up.
Again, you'll probably only need to worry about this during sheds if your corn is having issues. Also, you don't want to constantly mist, or keep the humidity in the cage too high. It can lead to a respiratory infection.