How many lortabs is safe to take a day? an how often?

Only and only: The prescribing physician can provide you with an individualized answer.

It isn't a contest : You prescription bottle will have strict instructions. If you need to go beyond the dosing recommended, call your doctor. It is very important that they know. They need to be on the same page and be fully aware of how much pain you are having, and guide the next step. If you are sleepy, you have taken too much, call an ambulance and go to hospital. Don't try driving yourself.