As the math was explained to me, they consider your odds of death with surgery versus your odds of death without it. As long as your odds of death are better in waiting, they will wait. Once the scales tip, they recommend surgery. Some of us choose to take some risk in deciding when, though, as I probably could have had my surgery months earlier than I did, but chose to wait until a better time in my life. My cardio and I have a wonderful working relationship, so I was and am confident that he would have been very clear with me if he felt it not prudent or safe for me to wait.
All of our cases are different. Listen to your body, but don't talk yourself into doing anything foolish, like waiting too long. You could do irreversible damage.