This again depends on what the clients are looking for. There are many stories where
models start picking up jobs from the moment, they sign up till 3 months after they sign up.
This can also depend on new trends, new fashions, and new companies.
It also largely depends on the amount of effort you put into it. You need to be persistent, motivated and committed. It can take months and months to even get your first casting, and only then if you are relentlessly pursuing your goal.