Longer any cycle goes, the greater the potential for side effects and a more complete supression of natural test. Being a newbie, you presumably are lacking in the side effects combatting and pct departments so it makes sense to limit your exposure. Additionally, you will get better results IMO from 8 weeks on 8 weeks off twice than you will from 16 weeks on and 16 weeks off. Just a dumb example of two ways to spend the same time on gear, but you get the drift. Gains tail off after time and you do better to recharge and solidfy the gains then ramp up again.