I find stretching useful particularly after doing several long runs in a row. My usual routine takes about 20 minutes, but I can be done in 12 if I am pressed for time. Over time I learned to know when I need to stretch. Not wanting to get up from a chair would be one example. The best stretch is the one you have not done for a while. I prefer not to listen to music and stretch in silence. It is good for concentration, and I stretch better. For me stretching feels as much a mental exercise as it is a physical one. Maybe because I have not done stretching for most of my adult life even after becoming a runner, I feel like I grow my mind by stretching. Stretching helped me stay injury free whereas before I often had Achilles tendinitis. When I stretch I feel the same way when I clean my house on the weekend: this is important and cannot be neglected. Especially as time passes by and I am getting older.