It depends what you really mean by 'learn'. I have heard it said that there are certain levels of insight that you can gain only after meditating constantly for

It depends what you really mean by 'learn'. I have heard it said that there are certain levels of insight that you can gain only after meditating constantly for a long period of time such as 10 days. You can however certainly learn how to get started, and reap benefits, from Vipassana in just 20 minutes a day.