Bonsai trees are known for having a long life span, much longer than their parent trees, but
why is this?
In short, there is no direct answer to how long will your bonsai tree live for. When growing a bonsai tree, the attention to detail and the protection that bonsai has is much greater than that of a normal tree, which will of course extend its life comparative to that of its parent tree. The bonsai tends to be pretty sheltered against potential life threatening problems such as extreme weather, diseases and the usual pests that can plague trees. Not only that, being that most bonsai trees are grown indoors for the majority of the year, their environment can be easily manipulated to provide perfect growing conditions for the bonsai, meaning the bonsai should live for longer.
So in conclusion, no one can tell you how long your bonsai tree will live for as there as so many different species of tree. I would recommend researching the average life span of the parent tree, then working from there.