Every practice seems to have parts that are great, even fantastic, others are disappointing. My vinyasas were not so good, my concentration was good. I practiced without breaks. The reward: I'm ready with my yoga practice and it's still early. The sun is shining, it's getting warmer here and I want to go out.
As an Ashtangi practitioner one has to be organised well, the practice is time intensive. It's true these timers make a lot of noise as well during the time when they run and at the end. A commented that she almost got a heart attack once when it rang at the end. I almost fell of the sofa, not only once, when it rang after 25 min. Nevertheless to work in 25 min steps is good, the best method that I know. I'm fine-tuning this method. After having worked for 25 min I write down what I've done. This motivates to keep going. At the end of the day I can see how productive I've been. (Hopefully.)
Time to eat and to go out.