I'd like to give my view on that topic, even if the question is already old. I started sitting at a martial arts dojo once in a month without any sect or tradition. The second pillar was a book from Sekida ("Zen-Training" in german). He suggested to count your breath and while I was sitting mostly alone at home and had no real training, even at that dojo, I followed that advice and it worked very well for me.
I have to admit, since know, I haven't sit regular. It was something like "a few days in a row" than a few days not. Over time I stopped practice and started again.
Now I sit with Soto-Shu once a week and every day at home. We do Shikantaza. With the random training before I was able to adopt that way quickly. But when it comes to long periods or I have a troubled mind, I go back to counting my breath, just to stay on track. I do two or three cycle and then stop counting again.
While I see the help breath-counting brings for concentration, I found for myself, that with enough training, I can count in a half conscious part of my brain, while thinking about other things in a different part. I still now the next count and I still restart after ten. Just training.
And for me, there is always the danger of counting breath as a measurement of how long I still have to sit, since my breath is deep and low and of quite stable frequency. In my consideration that is just as unuseful as daydreaming.