Thanks for the detailed information, that's really helpful! I have a 90GB system partition, which I now similarly regret as being a bit on the tight side! I use the rest of the (512GB) SSD for VMs, and anything else I want to be fast, so I wanted to keep plenty of space for that when I was deciding partition sizes. I understimated how much my Windows 10 install would grow over time! It hasn't got to the stage where I need to repartition the drive just yet though. I have about 20GB free, according to Windows, which is just about okay, as you say.
Yes, I feel I was perhaps inaccurate using the term "wear", so apologies for my looseness of teminology:
What I meant to refer to was the typical slowdowns in speed that the ReadSpeed benchmark is revealing on these forums. I don't think it is "wear" in the sense of wearing out. It seems that speeds can be improved somewhat by running Spinrite at level 2 (read only), or even more by running level 3 (which reads and writes back to the drive, so will increase the long term wear on the drive, but generally not considered significant enough to worry about). If you don't have access to Spinrite, then there are discussions around the forums about other ways of improving drives performance.
Having said that, congratuations on your new Samsung SSD!
They seem to be of very good quality (disclaimer: I do own one myself so am biased!), and your old OCZ is still doing really well for 10 years of service! Once you've got the new drive installed, you can maybe explore the ways of improving the OCZ drive's speeds. And if so, do let us know how you get on?