That poor kid! Of course, any constriction tight enough to stop urine flow is also going to stop blood flow..and couple that with normal nocturnal erections, that kid really could have had some serious long term problems. Hope he didn't.
the thing I like about the adjustable rings is you can put it on, then tighten it to your comfort level. I am NOT talking about using these in conjunction with a pump. Those rings with the pump hurt me and I did not like them. The adjustable rings are comfortable and you will find that they will need to be loosened or tightened a bit differently each time. Yes, i use them with viagra and the combination of extra blood flow and a bit of a noose around the base makes for a very usable erection most of the time. True, somedays, as we all know, nothing is gonna wake the thing up, but a ring is a big help overall.
Yes, half an hour is about the right amount for a tight ring, but the adjustable rings - because they tend to be a bit looser - can be left on longer. you can certainly tell when it's time to take it off - things will just get sore.
One more word of caution. Do get the ring made of a rubber tube - NOT the one with the plastic line. The tube is much more comfortable. The plastic line digs in too much.
Experiment and have fun. while you're in the store, take a look at other things you might want to try. Life and sex has changed for all of us...it just requires a bit more imagination and fun!