Re: About how long
I'll take a wild guess, and assume you are asking about Virginia Bright Leaf.
At room temperature (e.g. ~70°F), with the color-cured leaf maintained in low case (not dry, but flexible) in a vapor-proof container, it will probably require 6 to 24 months to age it as well as can be expected. It will likely be "smokable" before that, but will smell and taste "grassy" and unfinished. If, upon opening the container, you sense the aroma of ammonia, then it's not ready yet.
Bob