on what...how much...what are you eating...how long you been lifting...etc...etc...et c.
this question is insufficient for a reasonable reply
Agreed.
A few things though, if you're going for size, you want volume. Your muscles will repair freakishly fast on gear so hit them often.
Say your chest grows 1/16th of an inch after a hard chest workout on gear, why would you only do it once a week? This is a ridiculously simple scenario I know, but the logic holds true.
We do need some more info though.