The most common cause for this failure is the belt being too tight.
This causes a side load on the pump and alternator
leading to bearing/seal failure.
All too often people put a bar and pry the alternator
till the belt is "bar tight".
That is not the way it is done.
I am hesitant to post the proper method due to liability issues.....ask your local mechanic
and tell us what he says....I will agree or disagree with you.