What factors impact the cost of a new front door?

Front doors can take a beating over the course of its operational lifetime.  Your entry door, sliding patio door, and garage door are most likely opened and closed a dozen times a day or more.  And over time, effects from rain, wind, and the sun's rays can damage your door.  All of this wear-and-tear can create problems with how effective the door is concerning energy efficiency, operation, and security.