I know this post is late.
I took ashwagandha KSM 66 for well over a year, I just stopped it on the 12th July, no withdrwals.
I should have had breaks but it helped me sleep and addressed cortisol, so I didn't.
I was worried about withdrawals as people on Reddit got irritable etc, on breaks, but I am ok, maybe as I take other stuff like 5-htp, l-tyrosine, l-theanine, mag glycinate.
It seemed to take a few weeks to kick in but was worth it when it did.
I look forward to starting it again, whenever I find out how soon I can, I posted that question on r/ashwagandha, a subreddit.