Refactor example

void Start () {
    float scale = (transform.localScale.x + transform.localScale.y + transform.localScale.z) *0.3f;
    Mesh mesh = gameObject.GetComponent<MeshFilter>().mesh;
    Vector3[] peturbedVertices = new Vector3[mesh.vertices.Length];

    for (int i = 0; i < mesh.vertices.Length; i++) {
        peturbedVertices[i] = mesh.vertices[i] + Random.onUnitSphere * .1f * scale;
    }
    mesh.vertices = peturbedVertices;
    mesh.RecalculateNormals ();
}