I've been following the girth portion of [words=http://www.mattersofsize.com/forum/showthread.php?64036-My-Best-Work-Ever-Penis-Enlargement-will-Be-Changed-Forever-gt-gt-Gain%20inches%20with%20SRT-Theory-and-Routine]SRT[/words] (will be going all in once I can spring for a [words=https://shop.mattersofsize.com/products/sizegenetics-penis-extender]sizegenetics[/words]) and I'm wearing the cockring 3-4 hours after my session. Here's what I can tell you:
1) Once I've finished my last set of SSJs, I get myself fully erect, then reverse kegel as hard as I can to get even MORE erect, then strap on the cockring.
2) I take the cockring off periodically just to let some fresh blood circulate. Generally I do this every time I feel my dick getting cold. Once or twice an hour.
3) In addition to this, once every hour or 2 I will take the ring off and look at adult entertainment and edge for 5 minutes or so, and then reverse kegel in a fully hard and expanded state and put the ring back on (and by the way, feeling your dick in your hand when it's in this beefed up state is totally amazing lol).
4) I keep this up for as long as I can, but usually after 3 or 4 hours the ring starts majorly chaffing my dick, so that's when I finish up for the day. I'm working on ways to go even longer with the ring, but from what DLD says above even 2-3 hours is really good.
5) I do my girth work in the morning or in the afternoon, so I don't wear the ring up until bed. Supposedly you can, but you're not supposed to sleep in it. But this isn't an issue for me anyway because I do it earlier in the day and am usually way too sore to wear it up until I'm ready to sleep.
Hope that helps