This is a picture of a typical vent repair done by a roofer. This vent had been chewed but now has been fixed by changing out the flashing and installing a screen. Thats fine, it will last quite a while. But the cost of this was at least 150 dollars and required shingle pulls which often result in ugly repairs. A Critter Quitter would be 30 dollars and require no shingle pulls. Plus a Critter Quitter lasts decades. Something to consider.