For all the Tin Cup fans
http://www.youtube.com/watch?v=8mWKIMGinvg
As far as the Rules and the "One Ball Condition"
http://golf.about.com/cs/rulesofgolf/a/rulefaq_oneball.htm
As Far as Golf Ball Lifespan...this came from Answers.com
Ernie Els said there is only one birdie in a golf ball. On the pro tours a ball would only last around 6 holes, because the cover is so soft (Titlesit Pro V 1, Callaway HX, Taylormade TP) and the grooves are so sharp. An amateur could basically use a golf ball until they lose it. A golf ball if hit continously, depending on what type it is could last around 20 rounds before it would become dead.
WGT wants to provide the most realistic golfing experience. Since PGA Tour Players arent paying for their balls I guess WGT lets us keep them longer than the big boys.
But killing a ball mid round is just silly. I'd mention clubs but someone has already kidded about that . I'm off to the Pro Shop to stock up on tees, a new glove and some replacement soft spikes. LOL