In software history, certain versions become legendary: Windows XP SP2, Mac OS Snow Leopard, Adobe CS6. For the SketchUp community, holds a similar place. It represents the peak of the "perpetual license era" before Trimble fully committed to SaaS (Software as a Service).
To run this version smoothly, ensure your hardware meets these standards: What PC/Mac do I need for SketchUp? - CAD Software Direct SketchUp Pro 2019 19.3.252