Volumes are the preferred way to [https://docs.docker.com/get-started/05_persisting_data/ persist data in Docker containers] and services.
Bind mounts are a way to share a directory from the host (typically your app source code) into a running container and have the container respond immediately to changes made to files on the host. If your containerized app is a [[nodejs]] app, and needs to be restarted to "see" changes, you can wrap <code>node</code> with [https://www.npmjs.com/package/nodemon nodemon] which monitors files for changes and restarts the node app based on those files. PHP apps execute the newest code on each request (via the web server) and so do not require any special wrapper.