In most cases, meshes are closed polyhedrons, and one vertice typically belong to at least 3/4 triangles.
This means that if you don’t want to optimize your vertex buffer, its size would be 3 to 4 times larger. You may do it for small meshes, but when it gets large, it’s better to get it optimized.
Right now I started working on a MeshBuilder class as you see in this thread from yesterday.
It will make things more simple, I’ll be glad to share when done 