When do i know i have exersized enough with cad?

Check with your doc: In general, 30 minutes of exercise per day at a level you cannot complete a sentence is what is recommended, once you complete cardiac rehab (if after surgery or stent). Check with your doctor first.

Depends: An exercise program or cardiac rehab is generally good in patients with CAD. Ask your doctor. The upper limit is not known but excessive exercise is bad. Clearly moving away from a sedentary lifestyle is good. Exercising (brisk walk or more) 3-4 times a week for 30 mins is associated with improvement in many measures ie quality and quantity of life.

Stop if you feel bad: assuming you feel good with exercise, and don't have any angina and your heart function is fairly normal - then exercise is good for you; if you've had cardiac rehab then you may be familiar with the level of exercise they had you do. generally an hour of exercise most days of the week is best. too much is better than not enough, stop if you feel poorly, or have chest ache. review with your MD