This is a subject dear to my heart. I have started doing more chastity play in the past few years, mainly because devices have gotten better and technology makes monitoring and keyholding easier.

I concur with you for the most part about a gradual increase in length but it depends greatly on the sub. As far as what it too long, I definitely agree that an orgasm a month is a requirement. One reason is prostate health as you mentioned and the other is that a sub needs to remember what he is missing. At some point just being locked away offers no challenge. Now, I didn't say it had to be a good orgasm . . . ;-)