Allan, I think it makes sense to keep up to date with SketchUp as long as the operating system on your computer can handle it. SketchUp 8 is pretty old now and there are some web-based features that no longer work with it (or SU2013). But for what I plan to cover in January, I don't think it'll matter much which version you have.
If you do update to SU2016, you'll probably want to go for SketchUp 2016 Make. I believe you'll start with a 30-day trial of the pro version but after that it'll go to Make and disable the pro features unless you decide to get the license.
If you do update to SU2016, you'll probably want to go for SketchUp 2016 Make. I believe you'll start with a 30-day trial of the pro version but after that it'll go to Make and disable the pro features unless you decide to get the license.