A friend of mine told a story from when she attended a yoga workshop, where the tutor would frequently ask the same question every day:
Did you do your practice today?
He never asked how much time they had practiced, nor if it had gone well.
Back when I started practicing yoga, I remember reading that practice could vary significantly day to day. Some days you’d arrive at an incredible meditative space and experience a great inner calm, and other days it would be a routine to get over with as fast as possible, making it difficult to find peace of mind. But either way, above all else, it’s crucial to stick to it. Discipline and structure is needed in yoga to get the most out of it, and by practicing every day, you’ll naturally make the most of it every time, rather than once or twice a week. You can always vary the yoga so that some days it might be more active and physically challenging, and other days more gentle and calm.
Personally I find this to have the greatest impact in regards mental stamina, since if I miss out practice during a short period, my mind becomes more easily fatigued and exhausted, and when I return to my yoga practice, I quickly regain that mental endurance and energy.
In my opinion, the teachers question was quite apt. It’s not all about whether you could reach your toes, or whether you achieved absolute inner peace when practicing. It’s all about the discipline, and sticking to it to get the most out of it, both physically and mentally.