I did the cycle/pct/time off thing for my first couple of cycles and while I do see doing them in the beginning as a good thing to determine whether or not you truly want to keep going in this sport/hobby (whatever you consider it), the highs and lows of coming off and going on are terrible. Am thankful I did because I was positive I wanted to stay on and cruise during the down time between blasts and not have to do everything imaginable to kickstart my endogenous test levels and then take time off struggling to hold onto the muscle I gained before I jumped back on again.
My blasts and cruises are factored into three main factors currently. Health, finances, and life outside of bodybuilding. Currently, I'm pretty young still and my bloodwork has never been an issue for me to end a blast. The two main factors for me right now are finances and life outside of bodybuilding as I'm finishing up my degree that I'm paying for, so gotta account for that. Won't drop more than I can reasonably afford and if I'm taking particularly hard classes, I won't blast with anything that gives me harsh enough sides that'll prevent me from getting the best grades I can. Once I graduate and get in my career, I imagine these will factor a little less (until/if I start a family) and health will take more precedence.
So ultimately, it depends on those factors for me. Or if I need a mental break I'll cruise for a few weeks until I'm feeling fresh again.