For an average person learning a new motor skill or pattern takes something like 300-500 correct repetitions. To modify an existing motor pattern can take 3000-5000 correct repetitions.
I guess the way to answer your question is to ask yourself are all your volleys at an autonomous stage of learning?
I tweet - @ashtennis guru (no spaces)
I Shoot - www.flickr.com/photos/ashtennis guru/ (again no spaces! grrr)