Fairly anecdotal but for me it took just over 4 months of sitting on my butt (once or twice for about 20 minutes a day) before I "got" it. Once whatever it is that clicked for me, I was able to step into a deep state (deep for me, anyways) in about 5 minutes.

I've fallen out of practice (and am failing to keep my new year's resolution!), but I would very much like to get back in to it. The resilience it can provide almost feels like having a secret weapon.

YMMV. Ehipassiko!