Earlier quoted context omitted.
>As a result, when you end your cycle, your body needs to restart its natural test production. There can be a delay while this happens and it leads to unpleasant, though temporary, side effects, like weight gain and a loss of sexual appetite. Why not just slowly taper it off?
Test is injected into muscles, usually once every 2-4 weeks. It can't be taken orally. This makes dosage control difficult. The long half-life also means that your body's control systems are slow to act (if they reacted quickly then you'd risk ending up with too much, and be unable to get rid of it).
Also there are several steroids with different half-lives, so you can pick the best for your case.