When we are first learning to meditate it’s important not to sit for too long. We can start to slowly increase our time meditating if desired, in a similar way as we might do with physical exercise. So, 10 minutes a day is a perfect starting point.
It’s perfectly fine to continue meditating for just 10 minutes a day, you will definitely see considerable benefits such as being more aware, present, focused, etc. no matter how long you meditate.
However, if you have both the time and the inclination and would like to sit for a longer period of time, then that can definitely be very beneficial to your practice. Most people say that at first it feels more difficult to sit for a longer duration, but after a few days of adjusting, they can’t imagine sitting for less. It’s useful to remember that both the body and mind will adapt very quickly.
The one thing that changes as you sit for a longer period of time is the amount of clarity you may achieve. The reason for this is that it doesn’t take very long for the mind to settle down, and only then do we see the mind clearly. In some cases this can feel a bit like a magnifying glass or microscope slowly coming into focus, all of its own accord.
Ultimately though, quality is more important than quantity. Even one single moment of awareness is valuable. So choose a duration that works for you, build up slowly and without putting any unnecessary pressure on yourself, try to tease it up over time.