There are posts on occasion saying Critter Quitters are expensive. That’s all relative. If you call a roofer, assuming you can get one to come over and look, they are going to charge far more than a Critter Quitter to repair the vent, pull shingles, and potentially leave an ugly repair. If you install screens, you have to repair the vent first somehow with tape or expansion foam. Neither one looks good or will last, and screens done correctly are time consuming. How about painting the vent? Once again you have to fix it first, and even then the paint will wear away over time. Critter Quitters last the life of the house, so for the price they are a bargain.