I've been using the extender for about a month now, with about 140 hours of use. I started first by just wearing it everyday all week and by the third or fourth day I was extremely sensitive. After a couple weeks I took almost a whole week off. When I started back again the sensitivity was completely gone and I felt I could apply more pressure without the discomfort as before. After that I've adopted a weekly and almost daily schedule. I use the extender rigorously for 3 days, one day completely off and then 3 more days on, one day off, 3 on, 1 off. The three days on I complete about 6 hours of stretching each day in 3 two hour sessions in which I build the tension from 1200g to max and then beyond that a little. I also do some manual excercising like jelqing between the 2 hour sessions. By the end of the third day I've gotten fairly sore and the complete 24 or more hours off is greatly needed. On the day off I don't use the extender at all and just do either some manual excercises, or if the girlfriend comes over a nice total body workout.
I find this schedule has been very good for me and the day off allows me to come back the first day back on and really get a serious stretch on without the sensitivity. If I've been able to do more than 6 hours of stretching per day, say over a long weekend, I tend to spend a second day off to recover a little more. In a month, with a whole week off in there, I've noticed a 1/4" erect length increase and my flaccid state has changed greatly. At one time I used to never let my girlfriend see my penis without getting it slightly erect because my flaccid state was so embarassingly small while my erect size of 7" isn't that bad. Stick with it and try to find a schedule or routine that's good for you, but I definitely recomment splitting it up into a 3/1 or 4/1 schedule to give your penis a rest. Being a college athlete, we train hard for 5 days, tapering down until game day with a whole day rest before. Well the same principle applies to this extender I think, some rest will help you recover and keep from getting overly sensitive.