You haven't needed to manually defragment hard drives in Windows in decades.

Yes you do. In fact in Windows/NTFS you can lose gigs of space from disk fragmentation.

The system does it automatically and has since at least Vista, probably XP. Furthermore, there's no benefit (and in fact active harm) to defragging an SSD.

He talks about HD's, on Windows 10 you cant de-frag ssd's just optimize, aka trim. But de-frag HD's is often needed on windows in certain work scenarios.

Windows 10, just like Windows 8 and 7, automatically defragments spinning drives once a week. You never need to manually do it.

And? Maybe it's needed to be more often or not at all. However in Windows 10 you cannot defrag (with internal tools) SSD's like you wrote.

I never said you could. I said that you didn't need to defrag manually, and that with the rise of SSDs doing so would be actively harmful.

Windows usually does it automatically as part of a maintenance routine. Unless you were writing and deleting lots of files causing fragmentation, there isnt usually much to gain with manual runs.

I used to obsessively defrag my drives and it made very little difference. So much happier switching to SSD.