Multiple Box colliders on GameObject instead of Mesh collider

Can I add say three 3D Box Colliders to a game object instead of using a mesh collider?

Three box colliders would be far quicker to work with than a mesh collider with thousands of vertices and triangles. I can closely approximate the shape I need for collisions with three boxes, but is there any issue when you add more than one collider (of the same type or different type) to an object?

And what about if the Box colliders are overlapping? Is this okay, or is it better if they are not overlapping each other?

Thanks

Yes, you can have multiple box colliders, and then can overlap. Another thing to try is to keep the mesh collider, and then tell it to calculate a convex collider.