This must be meditation week. I've seen two posts about it (My Meditative Journey So Far (Learning Meditation) and 4 Powerful Reasons to Meditate and How to Get Started ). One thing that has come up is using an alarm clock to signal the end of the meditation period. Some people seem to do so, others don't. Should we use an alarm to signal the end of our meditation period?
Short Answer - No.
Medium Answer - It depends on how accomplished a meditator you are.
Long Answer - When you're learning to meditate, people often recommend meditating for a certain period of time. It may be 10 minutes. It may be 20. It may be 60. These are just guidelines. They can be useful, especially if you're as anal or OCD as I am. You want specific guidelines. You want to know you're doing it right. Remember, these are just guidelines. Doing it right doesn't depend on how long you meditate.
One of the purposes of meditation is to help us learn to focus on what is happening here and now. If you set an alarm to signal the end of your meditation, you'll set up an expectation that you will stop at a specific point in time. This pulls your focus from now, to the future. The internal division it sets up makes it harder to meditate. Think about when you were in school. You knew what time the bell would ring to signal the end of class. As the time approached for it to go off, how often did you more and more frequently distract yourself from what you were doing to check the time? If you were anything like me, you did it pretty frequently.
Rather than set an alarm, meditate at a time of day when your time isn't so tight you have to worry about the minutes. Especially when you are new at meditation, meditating too long will not be a issue. Feeling that a long time has passed when only minutes have gone by is the much more likely occurrence. If you do feel your time is up, your attention has already been drawn from your object of meditation, so you may as well look at a clock, then go back to your meditation the same as you would with any other distraction.
I wonder if my time's up? (glance at clock) Not yet. Back to my breath.
On the other hand, once you are an experienced meditator, you may find yourself so deeply in the state that you can go for hours. In that case, time may be an issue and setting an alarm can be helpful. By this point in your learning, you are able to set the alarm, then forget about it as you focus on your object of meditation. It isn't until the alarm goes off that it may actually impinge on your awareness. The act of setting it doesn't divide your awareness the way it does when meditation is new to you, but my experience is that it still has some divisive influence.
As you become even more experienced, if you're using a concentrative meditation, there's a good chance you will never hear the alarm, but by this time your innate time sense will cause you to start returning to normal consciousness in order to carry on the other activities of your day.
When I first started meditating, I often set an alarm to signal the end. I gave it because it causes more difficulties than it solves.