My dog is super intense in play and in everything she does. So I always make sure that whenever I throw the ball, she cannot see where it lands or lies. Otherwise she would have to put on the brakes too much and very possibly injuring herself. This requires good obedience and impulse control as she has to wait until I release her verbally. If I mess up throwing and the toy lands in a dangerous spot (black berry patch (her eyes!), or on a concrete area, I can put her in a down stay and fetch the ball myself.
She is 3 years old and very obedient (not spoiled rotten, I personally hate that term) so once in a while I let her keep the toy with the command "YOURS!" and when I want it back she complies.
BTW: some of you may remember that I had trouble with her releasing the toy a few weeks ago, but going inside, after she held on to it (only once!!), took 100% care of that one!