this is just the same old argument about blasting and cruising vs. cycles. Ya if u run for a year straight (or more) ur gonna have 3-4 months that really suck if u come completely off or u might need TRT for the rest of your life doses vary from 150mg-200mg test cyp for trt, which generally puts u on the very high side of the testosterone levels for an "average" person.
Yes cycling will probably damage your natural production less however if you dont ever want to be on HRT or TRT you shouldnt be using steroids to begin with. I persoanlly do not see unless u want to be a REAL bodybuilding and do competitions why anyone should use steroids. And personal variances between people are too great to come up with ohh run for only 16 weeks and ull be ok but if u run for 20 ur ****ed. The younger you are the better your body is at recovering if ur 35+ and running **** u might as well just goto the doctor and sign up for HRT right now cause ur not gonna recover half as fast as soemone younger.
To answer ur question about time off= time on + pct, that i feel is more directed towards oral steroids, where the prolonging cycles would benefit the liver because of damage done to the liver during that period. The technical answer is you can run ur next cycle once ur HPTA is back to normal (assuming u got pre-cycle bloodwork done and know what normal is).
Lastly i am going to stress running cycles is less effective than blasting and cruising, this is making the assumption you are trying to compete at bodybuilding or at an elite level of athletics.
As for heath reasons, any chronic abuse of any drug is bad for you obviously the longer you stay on the worse it will get but dont think 6 weeks on will leave u untouched and in just as good condition as when u started, there are drawbacks to every chemical you choose to put in ur body.
I personally have chosen to blast and cruise my cruises are 200mg test cyp (perscribed HRT). And compared to when i tried cycling the gains stay way better, even improve in some aspects.
Again this is personal preference and as to why u are using steroids. If u wanna get ripped up and goto the club during spring break then ya cycles are probably what u want. if u wanna compete and be strong and perform better you probably want to blast and cruise.
Im sure ill get flamed for this cause god forbid i said that people who want the most out of training never come off, however mention one pro-bodybuilder that comes off... cause there are none that i know of, and their "off" is generally around a gram of test a week.