I have felt that strength training is becoming a limiter of mine in terms of fitness and sports performance. For most of my life, I have strength trained with free weights and machines primarily for aesthetics and general fitness. Any significant improvement was the result of being in the weight room at least 4 days/week for an hour. This combined with having core training partners made all the difference for me.
As I have gotten involved in triathlon, my daily workouts are typically running or swimming. In fact during 2011, I only managed 32 hours of strength training (35-40 minutes/week). This is obviously not enough to stimulate muscle hypertrophy.
2012 has started off a little better. I managed 1-3 strength training sessions/week and the typical duration was 30-40 minutes. Ideally I would manage 3 sessions per week. However to see benefits, most recommendations call for hitting a muscle group every 3 days. My best bet to do this is either early AM or late PM sessions.