FYI, I still use the free version of Sketchup 2017 for quick and dirty drawings and occasionally download drawings from 3D warehouse. 3D warehouse will no longer download into the 2017 format so what I typically have to do is open them in the current free online version and export it to my PC in the 2017 format. When I exported one the other day, a message popped up saying that they will no longer support those older versions after January 31st so it looks like another strike against continuing to use Sketchup unless you want to pay for it. I was still able to upload a 2017 drawing into the 3D warehouse this week and it didn't say anything about the support for that ending but I suspect that may be happening soon too.
Time to spend a little more time honing my OnShape skills so that I can more easily do the quick prototyping that I often still do in Sketchup.
--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.