This has been a topic of discussion probably for as long as Penis Enlargement has been around. Maybe longer. There are a few threads around that address this, somewhat thoroughly, find those and you'll probably get a few good answers.
From what I remember, the question revolves around the hormones generated while erect and excited, holding off from orgasm supposedly keeps the penile tissue infused with the hormones, which can promote growth, for a far longer time than would happen had you had an orgasm.
Me, I haven't read anything completely convincing on either side of the debate. So, having said that, I'd say look at it from a percentage point of view: How many times have you edged and remained Master of Your Domain- divided by the amount of times you've come. If you're a proponent of the "don't come" theory, this'll give you a rough idea of the size of the bump on your Penis Enlargement road.
If you're a "it don't matter" kinda guy; then set 'dem swimmers free with abandon!