Probably from 2003 til late 2012, whenever I meditated, I think I usually did it for 20 minutes or more. The handful of times I've meditated in 2013, I've sat for 12 minutes. I think 12 minutes is probably a good duration for me. My partner recently shared an observation that I find fascinating, true, and helpful: the meditation itself might feel boring or like a waste of time, and it might not be enjoyable, and you might not notice any benefits afterward... but... being a person who meditates seems to have benefits. It's during your normal day-to-day life that you can find the benefits... such as being more aware of when your breathing gets shallow or when you're rubbing your face or pulling your hair... staying attentive to your body in order to listen to you subconscious or unconscious .. then stepping back to try to collect yourself and see a broader perspective. I hadn't thought about that before, but I totally agree that meditation has those delayed benefits. I wish it were easier to make that connection... then I'd be better about keeping up the habit. Anyhow, that's one of the reasons that I now think that the frequency of meditation might matter more than its duration (i.e. it doesn't need to be 20+ minutes each time, but I ought to do it multiple times per week if not daily or more).