How long does it take an insurance company to issue an automobile insurance policy after receiving deposit?

I've been with the same company almost five years. My car insurance is renewed every six months, after I make the required renewal deposit. Like clockwork, I receive the new payment coupons, and temporary insurance card. However, I don't get the permanent insurance card and new policy stating the value of my vehicle, until almost a month later. Sometimes longer. Is this legal? If so, why does it take so long for the agent to issue the new policy, and how will this effect me if I ever disagree with what's in the policy?