I can't really answer this well because I am horribly indisciplined in comparison with real religious although when I spent a year in a monastery I remember one of the really honest monks bring this subject up at teatime one afternoon and the tense silence and nervous titters that followed said more than an hour's conversation might have done.
The thing about monastic life is that there is no time for very much masturbation and the walls were so thin as well! I have never masturbated so rarely as when I was there . . .but the very lack of time and the difficulty of it made the experience extraordinarily satisfying: interesting contradiction. There was no doubt that the vigorous prayer-life and the constant singing [not to mention the constant companionship] did involve one emotionally as well as spiritually and an important aspect of a fulfilling sexual life has to be the emotional side of things. I do feel now that, had I stayed, I would have been able to integrate my sexuality into my personality more successfully than I have ever actually been able to. You could easily tell the monks who had achieved this 'synthesis': I always sensed that they were the ones who had really been called to the life and I think this 'synthesis' of the personality is what we are all called to. By this I do not mean that one would never masturbate because I believe it to be as natural as drinking or eating. It's really a question of how often. A giving and loving person just doesn't have the time.
In the eremitical life the problem becomes much more acute of course and perhaps this was one reason why St Benedict (founder of the Benedictine Order) stopped being a hermit and founded a monastery instead.
Isn't masturbation common in married life as well though?