It doesn’t hurt…but probably this is not a top tier factor in success. More important is the experience of your surgeon and the period of time that has passed since the vasectomy. The sooner a reversal is done after a vasectomy the better. Also, if one feels a knot in the area of the vasectomy site on each side, this is positive predictor of increased success. This is called a sperm granuloma and acts as a pop-off valve of sorts and protects the sperm making ability of the testicle.
As with everything in life…a little luck is always helpful!