Build tools and task runners are essential for modern software development, helping streamline and automate various processes involved in coding, building, and deploying applications. Tools like npm (Node Package Manager) and yarn are popular choices in this realm. They manage dependencies, which are libraries or packages your project needs to function correctly. When using npm or yarn, you can easily install, update, and remove packages through simple commands.

Moreover, these tools help in running scripts that automate tasks such as minifying code, running tests, or compiling assets. For example, you might have a script that bundles your JavaScript files or compiles your SCSS into CSS, and these tools can execute those tasks with a single command. By leveraging npm or yarn, developers can ensure consistency across different environments and save time by automating repetitive tasks.