for ghrp/ghrh one can "supposedly" use them year around, however one might argue that receptors sensitivity and desensitization can occur after sometime (how much, or even if it does, i'm not sure). Other peps, IGF/MGF/PEG, the trend is 4 weeks on, 4 weeks off i.e., IGF (4 wks) - off (4 wks) - IGF (4 wks) or even IGF (4 wks) - MGF (4 wks) - IGF (4 wks) and so on.
I hope this helps.