How much daily Yoga practice is enough?

Question: When your life is full of teaching and work and family, how do you fit in your personal practice as much as you'd like? Is it critical that you maintain a full Yoga practice (meditation, postures, breath work) during a time of busy-ness, or is that just my ego?
 
The benefits of practice build and go deeper if you practice daily. You find time for things you consider a priority. Prioritize your health, peace of mind, and relief from stress by doing your practice daily.
 
The question is: how much do you have to do to consider that you've done your formal practice? It's good to have a "daily minimum". If you have a do-able daily minimum, like 15 minutes of meditation and 3 sun salutations, then you'll really be able to do it and you get the benefit of the sadhana (spiritual practice). Plus your mind stops bugging you about doing your practice. It's even OK to have a minimum of 5 minutes of meditation and 1 pose. It's great if you can check it off your list first thing in the morning. But make it something you can do to calm down before bed even if you've been overwhelmed all day. 
 
Then you build in short sadhana times whenever you have to wait. Say a manthra or affirmation in line for the grocery store, chant when you're stuck in traffic. Read a spiritual book in the dentist waiting room, etc.
 
The more sincere you are, the more pressure you may put on yourself to do formal practice. That pressure may be the ego, indeed. You set a goal and the ego wants to succeed to feel good about itself. But that’s a good use of the ego. Your practice will help you and others, so it can help develop the sattwic (balanced) ego.
 
Sometimes the ego makes you try to do too much, then you give up because it's too hard. So you may want to start by setting a goal--then cut it in half. Stick with that for a while, and if it's very easy, increase gradually. If it's too much, cut again until you find what works for you. 
 
Do your daily minimum in a relaxed way, but be firm about sticking with it. Be encouraging and cheerful with yourself while training the mind and body. Talk to God (a higher power, your chosen idea of the ground of being) about your stress. ​You can cultivate the sense of being held, seen, and loved by a higher power while you do your practice. That will help you to want to do it.

When you practice regularly, it gets easier to keep it up. The habit becomes a part of your routine, and you start to feel the results. You will gradually feel more peace in your daily life even if your practice itself felt unfocused. Over time, many people  find that they  make more time for practice because it feels good. And they don't feel pressured. 

That's been my experience. Many years ago I set a goal of 15 minutes of meditation per day minimum. Over time that grew to where I rarely do less than an hour, even when I'm away from the Ashram. But on a super busy day, I still feel happy when I've fit in 15 minutes--that's non negotiable.
 
People often imagine they'll make time for spiritual practice when they're less busy. St. Frances de Sales said, "Half an hour's meditation each day is essential, except when you are busy. Then a full hour is needed." You need it most when you're busy so that you can keep your peace of mind. Yes, do an hour if you can. But if you can’t do that much, don’t let busy-ness keep you from doing your daily minimum.