Your windshield and windows allow you to see the road, so they should always be clear.
Don't hang anything on your rearview mirror. Nothing that could block your view (signs, objects) should be placed on your front or rear windshield. The only exceptions are windshield stickers in the following spots:
To keep your windshield clean, replace your wipers at least once per year. The older they get, the less effective they are.
Weather changes can cause your windshield to be covered in fog or frost. Your defroster is important for keeping your view clear, and should be maintained.
