Trimble has aggressively moved to subscription-only. No safe, legitimate, permanent free desktop license exists today. Use SketchUp Free (web) or switch to open-source alternatives.
The free SketchUp Classic license offered many of the core features that made SketchUp Pro popular, including the ability to create complex 3D models, use of the push-pull tool, and export models in various formats. However, it was not without its limitations. Users of the free version had limited export options, could not import certain file types, and lacked access to advanced features such as dynamic components and advanced rendering tools. Despite these limitations, SketchUp Classic provided a robust platform for users to learn and apply 3D modeling skills, making it an invaluable tool for educational purposes and for small projects. free sketchup classic license
The year was 2012. The golden age of the "Classic License." Trimble has aggressively moved to subscription-only