Developing a ten-year sinking fund plan means that future repairs and maintenance are anticipated well in advance. If the owners corporation has to pay a debt that was not budgeted for in either fund estimates, a special levy must be agreed at a general meeting and paid to the administrative fund in accordance with section 76 of the Strata Schemes Management Act 1996. An unpaid levy incurs interest at the rate of 10% simple interest a year if not paid within one month after it is due. The owners corporation is responsible for making sure all necessary insurance policies are in place in accordance with section 83 of the Strata Schemes Management Act 1996. The building must be valued every five years in accordance with section 85 of the Strata Schemes Management Act 1996. The owners corporation must keep certain records for at least 5 years including minutes of its meetings, correspondence, proxies and financial records. The owners corporation must prepare and keep a strata roll in accordance with section 96 of the Strata Schemes Management Act 1996 including the name and addresses of all lot owners, tenants, mortgagees, the original owner and the managing agent, the units of entitlement, insurance details and the by-laws for the strata scheme. The owners corporation must repair common property and lot owners must repair anything in their lot. However, this can be difficult as it is not always clear what is common property and what belongs to the lot owner. Starting 30 November 2016, cosmetic changes to the lot will not require the owners' corporation's approval. Minor and major renovations, including changes to floorboards or changes to the structural and external appearance of the building will still require approval of 50% (general resolution) and 75% (special resolution) respectively. There is no mandatory set of by-laws. Some model by-laws are set out in legislation, others are set by the original owner. By-laws can be added, changed or repealed at a general meeting if the motion passes. The owners corporation can engage a strata managing agent to work on behalf of all owners to help manage the strata scheme by entering into a managing agency agreement, which outlines their duties and responsibilities. The appointment of a managing agent can only be decided by a majority vote at a general meeting in accordance with section 27 as the Strata Schemes Management Act 1996. Agents carry out some or all of the functions or duties or powers of the owners corporation including administrative matters such as calling meetings and collecting levies. The owners corporation must elect an executive committee which can make many of the day-to-day decisions about running the strata scheme on its behalf rather than deciding matters purely at general meetings however the owners corporation can overrule executive committee decisions or limit what they can make decisions about.