The professional practitioner must consider the conditions of contract and any amendments to them in advance of seeking quotations for implementation of the works. Most commonly, the contractor is responsible for losses arising from theft or malicious damage prior to practical completion. The amount the contractor can expect to be paid on interim valuations might be reduced if, for example, the project involves a high proportion of planting or high value items such as semi-mature trees where the retention might otherwise not be enough to cover any losses sustained. The contractor is required to provide evidence of insurance cover against any negligence, breach of statutory duty, omission or default on the part of any person employed or engaged on the works by the contractor. The choice of which of the supplemental provisions are to apply is made in the Seventh Recital of the Contract Particulars.