Your only limit is your mind.

Mindfulness involves paying attention to what is going on inside and outside ourselves, moment by moment. It's easy to stop noticing the world around us. It's also easy to lose touch with the way our bodies are feeling and to end up living "in our heads" caught up in our thoughts without stopping to notice how those thoughts are driving our emotions and behaviour.
"An important part of mindfulness is reconnecting with our bodies and the sensations they experience." This means paying attention to the sights, sounds, smells and tastes of the present moment. That might be something as simple as the feel of a banister as we walk upstairs. Another important part of mindfulness is an awareness of our thoughts and feelings as they happen moment to moment.