>>41043410
>Is retaining enough to get all of the benefits, or is it mandatory to combine it with some kind of advanced spiritual practice?
tl;dr the latter and not just for all benefits but big share of any benefits

To elaborate:
Unlike what many overly eager beginners hope, if you already don't overdo your indulgence/stress your body too much and are in good health the benefits tend to be minor albeit valuable long-term. Anons who claim great effects, assuming they're honest, tend to be the ones who overtaxed themselves and the mere return to norm is the huge improvement they notice.

As mentioned before, if SR would be enough on its own to make one achieve new spiritual heights there wouldn't be any need for any spiritual practices as any random person who is in celibacy, with low/no libido or otherwise asexual would achieve divine spiritual mastery by default.
Semen retention is merely a habit and choice to build up and preserve certain resources. While they are (very) slowly being used and refined on their own at certain level, to achieve actual noticeable results in a span of single lifetime, you need to consciously use, allocate and refine that resource.