My concern (back then) with keeping the greens spun up would be that I’d lose the energy savings potential of them without the benefits of a purpose built NAS drive.

In my current NAS, I just have a pair of WD Red+. I don’t have a NVME cache or anything but it’s never been an issue given my limited needs.

I am starting to plan out my next NAS though, as the current on (Synology DS716+) has been running for a long time. I figure I can get a couple more years out of it, but I want to have something in the wings planned just in case. (seriously looking at a switch to TrueNas but grappling with price for HW vs appliance…). My hope is that SSDs drop on price enough to make the leap when the time comes.