2 at most? You're joking, right?
Your abdominal muscles are more resilient and recover more quickly than most other muscles. That's not to say that it's a good idea to work them every day - you should listen to your body. If the muscles are sore, don't work them. If they're not sore or the soreness is minimal, go ahead.
"I don't want them to like me, because when I'm in the ring, punches fly to the face. It is not a tenderness time. I am not falling in love. And he knows that when the fight starts I am kicking faces."
- Wanderlei Silva