Well, it's about practicing, not how many hours. Because life is short --even if we live 100 years-- we must not think that we are going to practice one hour, or 2 hours a day. It's not like that.
Yoga practice is not just about asanas. There is pranayama, and meditation. And there are thousands of different techniques of meditation. The ones I use belong to Anuyoga or Anuttara Tantra style.
Asana practice is about the quality of your practice. if we only feel your muscles, we are not getting to the point. Asana practice is about energy, feeling the prana as it has many forms in and outside the body.
Asana practice is to understand (not intellectually) how the body works, and how yoga works on our body, on our energy and on our mind.