While owning a pet can be fun and fulfilling, it comes with responsibilities too. Your pet can't make decisions about their medical care, so it's up to you to make sure they stay healthy. Here are some of the top reasons why you need to keep your pet's vaccinations up to date. 1. Pets can't tell you how they feel Your pet can't talk, and if they're ill, you may not realize it until they feel so bad that it affects their behavior.