Is it necessary to always use `dotenv.config()`?

No, you don't always need to use `dotenv.config()`. You can access environment variables directly from `process.env` after loading the `.env` file. For example, you could load the `.env` file once at the beginning of your application and then access variables like `process.env.DATABASE_URL` throughout your code. Using `dotenv.config()` often simplifies the loading process, but direct access is also valid and can be more efficient if you only need a few variables.