Time-on/off, 90 days, etc....I don't buy any of these. If you become shutdown completely, it can vary tremendously. You may think your T is back all the way and it may decieve you. Personally, if I were to run another cycle only a few months after the previous, I would DEFINTELY get a blood test to check liver, cholestrol, and especially hormones.
I ran ppplex for 2 week and then SD for 1 and had liver vaules in the 600's by the end of the cycle. In the first few days the vaules dropped to the 100's, but it took about the entire month after to return to normal. My lipids were insane, I had a very high risk factor, and my previous blood tests were awesome.
So, you must keep all of the invisible health things in mind. Just because you feel ready to go again doesn't mean its the case. Some people recover extremely fast...I've had friends say they were ready to go in 14 days!