I guess it varies from person to person. I'm trying the no adult entertainment / no fap diet and have started this on March 1st, so that will put me on 90 days pretty soon. During this time, I haven't masturbated/edged. I don't know much about the science behind it but, as others have said, holding it in is bad. Some people have the notion that if you don't use it you lose it. As I stated in my opening, it must vary from person to person because after almost being 90 days in, my EQ is way stronger than it was when I was "using" it and my length/girth has remained the same throughout this time. I also noticed my nerves are more sensitive down there, which may be a good or bad thing depending on how you look at it. I have attempted to do some manual girth work (
ssj) and have stayed harder longer than when I've done it in the past. I'd still like to have some pills on hand to help my sessions last longer though. I also have more control over my sex drive than when I was masturbating. All I used to think about was sex and finding ways of relieving myself (ie. going home straight to the computer and wasting hours looking at videos/pictures). Having sex with a partner is fine as that's the natural way of doing it but, masturbating,
IMO, is not.
Again, this is all based on my experience and it may be different for everyone else.
So long post short, and as others have said, do what works for you short of holding it in as that may have a negative impact on your health.