Three months. I just wanted to try out what happens. First 10 days or so were hard, pun intended, but after that you get used to it. My experience: You don't suddenly become an alpha male, and it had no measurable effects on strength training whatsoever. It might have improved the overall mood a little, however I suppose the mood is only bad in first place if you seriously had overdone it with masturbation beforehand, and even that might be individually different.
By far the most useful effect was the amount of time that was freed up. As a true enjoyer of things, masturbation can easily take up over an hour per day, even if you're not gooning. I suddenly had lots of time available. Is it worth having no orgasms? Probably not.