I've heard of priests who recommend praying the Rosary all day long, using your
fingers. They acknowledge that you don't get the indulgence you would if you
held beads, but they say the effect is powerful, as anyone who makes 15 decades
a day habitual will find that they do not lose the state of grace from day to day.
That says a lot.
My own experience with that is, that I'm easily distracted, and when I use my
fingers, or even one of those rosary-ring do-dads, I forget which decade I'm
on and I end up having to repeat decades. When I'm tired, sometimes one
rosary can take all day to finish, because I forget where I am, even whether
it's the Joyful, Sorrowful or Glorious Mysteries. I don't have that problem when
I hold rosary beads.