How do you know your comfortable? It requires "Being". Creating memories of comfort through awareness and recognition.
Why is it important to know when you are comfortable? Because then you can use the knowing to re-energize. When you are in the moment and savor the feeling of comfort, it brings you relief.
Think back to a time you were wearing a pair of closed-toed, full- covering your feet kind of shoes all day. You could be sitting or standing, moving or still - but your feet were confined in that shoe space for 8-12 hours.
Next try and recall the moment you took off your shoes. There's that sense of freedom, relief and comfort. Were you able to recall it?
If not, then next time you have this opportunity … FEEL IT !