I suppose on the exercises that are more girth oriented and focused on intense tissue expansion...any of the intense girth exercises really...you would probably need more "off days". However on length only exercises like stretching and hanging ....I personally think it's best to work those as many days a week as you can. Keeps the ligaments and tissues pliable and stretched. I for example am working a routine where I hang 4 hours total time per day...6 days a week...on the seventh day I hang at least an hour with some manual stretching after that. I stretch every little chance I get. Even if that stretch is just a quick downward or out to the sides tug at the toilet.
I have been wondering about this too. Some people say taking rest days is very important and going 6 or 7 days a week is not good at all. I don't really know. I have just been taking one rest day every week so that's like 6 days a week of consistent Penis Enlargement.
This question came up again and again on the "other" boards and I'd just like to to note that the super gainers - DLD, BIB and ULI did their exercises every day and in some cases twice per day or even all day!
Of course I would be the first to agree that everyone is different.
Either way, the key is in building up to it. NOBODY should jump right in to 7 days per week, in my opinion. Start off slow, & build up. But I do agree with stillwantmore, that length gains need to keep getting hit, don't give those ligs a chance to contract back to normal - until permanent gains have been cemented.
Girth is a little different, I never had any problem gaining girth. In fact, I gained girth the quickest while on an every-other-day routine (of course, I was a newbie then too).
But I think that time/frequency is most important with length - or how else could guys gain with hanging only 5-7 lbs (I pull much harder than that at times). And some guys gain with things like Penimaster, with only 1.5 lbs tension.
I'm seriously considering getting a Bib soon, money permitting. But I bet I pull harder than 15-20 lbs on a routine basis, yet length is stubborn for me. I may try doing 2 daily stretch sessions, starting at 12 minutes each, until I'm up to 2-3 sessions for a total of 60-75 minutes per day, 7 days per week.