re: New Desktop Build Recs

I know I'm going overboard, but I tend to do that with electronics. I was at a tech conference for accountants many years ago, and the guy leading the intro section said to look at gaming quality components, keyboards, mice, etc. Not because you need them, but because they will last and you won't need to replace them as often. My last build lasted 13 years, so who knows what I'll need 5 or 10 years from now.

I'm mainly wondering what has changed since my last build. Should I run dual channel 8gb memory or a single 16gb stick? Any benefit to using all 4 channels over just the 2?

I know I said I planned on reusing my old hard drives, which I have a mix of a sata SSD and regular sata HDD. What would I gain by switching to an m.2 NVMe drive?

Anything i need to worry about with my Windows license?