How often should I meditate?

Frequency has better supporting evidence than session length, though most of it is observational. In an analysis of 289,630 logged sessions, people practising four to seven days a week were 2.33 times as likely to reach their 150th session as those practising one day a week, and session length showed no association with mood change. Note that this predicts persistence rather than symptom improvement. One randomised trial that held the daily total constant found no advantage for splitting practice into two shorter sessions rather than one longer one.