Well I started doing billy blakes ab workout (from youtube) twice a day. I like how its half standing up and the rest is different kinds of crunches.

When do I change to a different one of his workouts? I want to workout 6 days a week with saturday off. Should I switch workouts every week? Or every day? Will the workout still be effective if i come back to it after I try other routines? I want to workout only abs and pecs right now. I have dumbells that i can put heavier/lighter weights on. You dont have to mention diets in your answer.

so... what's the best interval. I work out 1-2 hours a day, and play basketball. thanks