The length of our daily practice of meditation will vary according to one's level of experience. For those just getting started, the most important thing is to establish the routine, or habit of meditation in the same way that you have established other healthy habits, like drinking enough water, brushing your teeth, or bathing. Start with five to 10 minutes and be consistent daily. Regularity is essential in order to feel results, so remember that some meditation is always better than no meditation at all! Once you create a routine that anchors you into the intention of stillness, then slowly increase the actual time of sitting to 15 to 30 minutes.
(Why is it important to meditate with the right intention?)
As we become accustomed to meditation, this extension will happen rather spontaneously. We feel the peace and calm that come with regular time spent on the cushion, and we begin to desire more minutes in the state of tranquility and more time connecting with the inner Self. That being said, even long-time meditators may have days when they just feel too busy to make time for a practice, or too restless to settle in. We must be watchful of this because the temptation not to meditate is the ego trying to pull us away from the path that leads us back to our souls. Even if life is full to the brim with outer activities and even if the mind is filled with swirling thoughts, it is essential to maintain the consistency of our practice, albeit sometimes just a short one. Rather than deferring to how long our to-do list is on any given day, we can determine the period of time that feels reasonable and achievable and stick to it, no matter what.
If illness arises and you feel unable to sit or breathe comfortably, you can modify by simply turning your attention to the third eye point between the brows and taking a few moments to concentrate on the stillness within. This can be done from any position, and it helps to quiet the mind and body that may be distressed by illness. You could also try mentally repeating a mantra to direct your thought away from bodily discomfort.
(How do I see through my third eye?)
In any case, regularity is what counts most in terms of feeling the results of one's practice. So, choose a doable amount of time, based on your level of experience and the demands of your daily responsibilities, and commit to it. Dedication will deliver sure results.