Windows 10 Partition Size?

[ZeroG]

I've just physically installed a new 1TB NVMe drive into my system. My current OS is installed on a 500GB SSD but I was going to do a fresh install of Windows 10 onto the NVMe drive. Most of my games are installed onto a 6TB HDD, which is also used for storage, a few games are installed onto a 120GB SSD (but it's about 6 years old by now).

Now I was thinking I could partition the NVMe into OS/Programs and Games. That way I can have the games that would benefit most from the faster NVMe speed on the same drive as the OS but I could reinstall in the future if I ever needed to.

What would be a good size to make the OS partition for Windows 10, some programs and a bit of free space for Windows to do it's thing?

 

[ZeroG]

Thanks for the recommendations. Currently still going through backing up stuff I need and sorting out things I can keep and things I can ditch. I guess being able to increase the partition size later if absolutely required might help. I think I will probably set it at 120GB or 140GB for now and see how I get on with that.

I used to use CCleaner as part of my system maintenance but is that still the go to these days or are there better programs?