The genes you inherit from your parents are perhaps the most likely reason why you have bipolar disorder at all. However, things have to happen to you to cause you to slip into mania or into depression. In my experience, I have found that these triggers are usually well hidden in the surroundings and you can stumble upon them at any time. You must watch out.
All kinds of personal stresses that you come across day to day in your home or anywhere else can cause you to have episodes of bipolar disorder. The good thing about it is that you might be able to see these triggers about a mile away, and you should at that time choose to walk away from it before it takes you over.
One of the most infamous triggers of a manic-depressive episode in a bipolar-disorder sufferer is failure. It is a fact that there aren't a lot of people on this earth who can handle failure too well, and patients of this disorder are not on the good side of that list. If you suffer from this condition, you should have someone or something that helps you check how much your emotions are tied into what you do so that if you fail it won't break you.
Dealing with bipolar disorder can best be done with the assistance of a doctor or a medical practitioner. Irrespective of the triggers - either by stress or failure a doctor can assist you to handle the situation with ease using various medications and therapies for the condition.