time off = time on , may be optimal for health but is surely not optimal for gains. if your on for 16 weeks and then completely off for the next 16 weeks, then your leaving a lot of gains on the table.. its like training 6 months then taking 6 months off from the gym to let your joints heal , now sure your joints will be healthier, but your gains will suck. your better off training 11 months and taking just 1 month off.

same with AAS usage if bodybuilding is a high priority . phase cycling with compound rotation with just occasional short 'off times' is optimal . taking half the year off though , thats basically "half natty"