1. The document discusses 5 things the author learned while building a SaaS app with Vue.js, including that authentication is more complicated than most people think, component reuse requires planning, deploying to a CDN requires planning, third-party plugins should only be embraced conditionally, and Vue.js dev tools can save time. 2. It provides examples of component reuse by listing specific components like CheckDetail and EditApiCheck. 3. It promotes the author's product Checkly and provides his email and Twitter handle for signing up for the beta.