I've been on it for 6 months and haven't moved to R60 yet. Since I'm only at 3.5mg/wk, I recently began purchasing R30, mainly because my husband is now using it as well. A single vial shouldn't be kept in use beyond 3 mos. For me, about 8wks feels safer. My first purchase was a kit of R10, and after that I sized up according to how quickly my dose was increasing.