It's just that people aren't replaceable. When they are gone, there is nothing that can fill the space that their particular energy or personality's absence has left empty. That's what makes relationships so special. We are all unique. We matter. No one else can fill that space. And if it's your child?
Taking a babysitter along on the family vacation provides you with the freedom and support necessary to truly feel like you're on vacation. It gives you the flexibility to see sights that aren't kid friendly, enjoy nightlife, and participate in activities that are not possible when you're caring for young children.