To date there is no scientific evidence that long-term abstinence from orgasm has any benefits -- and there are studies that show it causes decreases in testosterone levels and prostate health (one theory is that among wild animals ie. lions or primates, long periods without ejaculating is correlated with limited or no access to females, which results in hampered testosterone production and the development of "beta male" physiological traits ie. smaller size, smaller mane, etc).
As is known, all of the support for Nofap is anecdotal and subjective, and most likely placebo. Studies do, however, indicate that short-term abstinence (1-2 weeks) without ejaculating can result in temporarily elevated testosterone levels, but that returns diminish over longer periods.
Personally, I find that not fapping for short periods of time does increase my social assertiveness. Whether this is the result of elevated T or simply psychosomatic, I can't say. There is a sensation of having a "loaded gun." However, after about a week without fapping, I find that I am often distracted by sexual thoughts and I actually become irritable and impatient in general. I have no desire to "rise above" that and continue blue-balling myself for the pseudo-scientific benefits of some internet-based monastic exercise in self-deprivation. Busting a nut a few times a week is perfectly healthy.
If you really want a boost in mental clarity, focus, sleep quality, testosterone production and sense of well-being, quit drinking. Completely. Remove alcohol from your life. The hormonal and mental benefits of sobriety are scientifically supported and are pretty obvious when you've gone a few weeks without a drink.