Code violations can sneak up on you if you don't stay abreast of changes. For instance, did you know that dryer venting screens are now code violations in a large part of the country? The code is changing in many other areas soon, and you may be in violation without knowing it.
Birds, squirrels and other animals are what the screens are supposed to keep out, but in the process, they keep lint in. This is a major fire hazard.
The DryerWallVent is a great solution to assist in keeping pests out without blocking the airflow, but if you absolutely must have extra protection, The Defender is available and features vertical bars instead of screens. These bars minimize lint buildup and make it very easy to clean.