Its just a standard protocol. I've seen people run longer oral cycles, but most report more side affects. I mean think about it. Any and all steroids are toxic to your liver. Injectables only pass the liver once, so the cycles are longer. Orals pass the liver twice, thus making them harder for the liver to metabolize. So basically its an acute toxicity issue, in terms of time spent "on". Besides, I've seen no evidence that people who run longer cycles (6-8 week) gain that much more than someone who runs a 3-4 week cycle. This is just my opinion, but I try to use the safest protocols known available because I still want to be reasonably healthy at middle age and beyond. In other words, I don't want to ruin my body and liver by the age of thirty, which is certainly possible by irresponsibly using steroids.