Of course, different traditions will have different meditation techniques of varying lengths. There are many, and best to follow one path where people don't experiment too much on you and themselves. That the same techniques have been practiced for a looong time (think: like a vaccine!).
As a "beginner" meditator, 20 mins a day is plenty though. As an "experienced" meditator 20 mins is enough too (you may in time meditate anytime/anywhere).
It's when people take on themselves to "do much more", mix several spiritual practices or follow cults that do extreme regimes that things might sometimes get crazy. Most people do OK, but there are people who need medication or have deep-rooted issues that maybe should not be doing meditation, at least not until those issues have been settled.
Another issue is that some deeper practices were basically developed for monks, to be learned after years of initiation and acceptance.
As a "beginner" meditator, 20 mins a day is plenty though. As an "experienced" meditator 20 mins is enough too (you may in time meditate anytime/anywhere).
It's when people take on themselves to "do much more", mix several spiritual practices or follow cults that do extreme regimes that things might sometimes get crazy. Most people do OK, but there are people who need medication or have deep-rooted issues that maybe should not be doing meditation, at least not until those issues have been settled.
Another issue is that some deeper practices were basically developed for monks, to be learned after years of initiation and acceptance.