I think at least 20 minutes a day you should be meditation for. You are just going to be missing so much of things when you don’t meditate. So just meditate! Clear the mind from all the crap that just clams up our thoughts and keeps us stuck. Start out with 20 minutes and then take it from there. Just have a practice, and you will start to have clarity that you never ever had before.
Some say that 15 minutes is okay. I would say that 15 minutes is the bare mininum. Any less than 15 minutes is just not enough time for the mind to settle down and relax. Five minutes is definetly not enough time.
Part of the reason that you are asking this question: How long should I Meditate for is you might be trying to find a shortcut. You realise that I have so many things to do and that I just don’t have the time to sit down and just be with myself in thoughts or prayer, but the truth is that you will end up getting all that much more accomplished. Sometimes after I meditate I find that I have a boost of energy to get a few more things accomplished in my working day, whereas had I not meditated because I felt that I just didn’t have the time then I verywell might not practice meditation.
I strongly feel that mediating for a half hour, two times a day brings a sense of balance to my life in that I am able to deal with the world around me. Why I like a half hour is that I get a chance to first deal with any pressing thougths and then at the very end I feel that I am able to reach a place of centered calm. If all I did was to spend just five minutes or ten minutes then that might not be a enough time to let the pressing matter settle down and then enter into a period of relaxation.