If you deploy does the army have to wait two years before deploying you again?

This is what I have heard. I know that a lot of the time there are exceptions to every rule the army has but I thought I heard once that if you deploy you get a minimum of two years rest before they deploy you again. If I were to volunteer for a deployment and then return to my unit, would this nullify the two year waiting period and I'd have to deploy with them if it were within the two years?