you need not worry about time off as much as you think if it's not months and months of consecutive detraining.your muscles have memory and they can regenerate to past volume faster than you may think.thats' a reason why i think site injection is important(for people who use gear).although it's only an inflammation of the site, you are causing your muscle fibers to expand w/ the inflammation. thats' why if you take off you months, but you frequently injected say delts; when you train them again, your delts say, "wow, i remember having more volume" and respond by growing to the previous size more rapidly.just my opinion on the whole thing