How your application uses memory is a critical performance indicator, and is especially important if you want to optimize your application for platforms with limited memory resources, such as low-end mobile devices.
In addition to the built-in Unity Profiler, you can use the Memory Profiler package to diagnose memory issues in your application. For more information on how to optimize memory performance in your application, see the Memory Profiler package documentation.
For further information on best practices around memory management, see the Learn tutorial on Memory management in Unity.