Once a desirable apartment unit or complex has been narrowed down, it is then time to compile the financial data pertaining to the compound. One must request for the building's financial history going back several years. Current rental collection records as well as another date including vacancy rates and annual maintenance costs. An evaluation of the property must be carried out by a professional evaluator based on similar complexes in the area. As a rule of thumb, one can expect 35% to 45% of the rent is a good estimate of the income to be expected within the first year. New development such as TRI-ZEN and other properties that offer 3 bedroom apartments in Colombo Sri Lanka, for example, evaluate higher as there are fewer properties with more than two bedrooms.