the general rule is time on + pct = time off. but i think if you dont take the full time off you should still keep the total amount on the ph's to 8 weeks at the most. alot of dudes do 8 week cycles. so if you do 4 weeks on. youre probably good to go with another 4 week cycle without waiting a full 8 weeks of time off. but thats just me. theres no real solid info on this that ive found so far.