For quick brainstorming and rough sketches, choose Excalidraw. Its charming hand-drawn aesthetic makes it perfect for developers sketching architecture or anyone needing a low-fidelity visual tool. It’s free, open source, and operates offline, keeping your data local. However, if you need polished diagrams or a comprehensive design tool, Excalidraw would not meet your needs.
On the other hand, if your main concern is managing disk space on Windows, opt for WinDirStat. It provides a clear visual representation of what's consuming your storage through its treemap feature, making it invaluable for Windows users looking to reclaim space. Although its interface feels dated and it can be slow on very large drives, it's completely free and open source. Avoid this tool if you prefer a modern UI or require cross-platform compatibility.