"Repair is restoration by renewal or replacement of subsidiary parts of the whole. Renewal, as distinguished from repair, is reconstruction of the entirety, meaning by the entirety not necessarily the whole, but substantially the whole subject matter under discussion ... it follows that the question of repair is in every case one of degree, and the test is whether the act to be done is one which in substance is the renewal or replacement of defective parts or the renewal or replacement of substantially the whole."
"It seems to me that the test, so far as one can give any test in these matters, is this: if the work done is the provision of something new for the benefit of the occupier, that is, properly speaking, an improvement; but if it is only the replacement of something already there, which has become dilapidated or worn out, then, albeit that it is a replacement by its modern equivalent, it comes within the category of repairs."