 Wooden houses are considered to have a lifespan of twenty years, and concrete ones to have a lifespan of thirty years, and the assessed price depreciates each year contrary to housing markets in other nations.Most real estate agents also use this pricing policy as a rough guide.Although there are still some wooden homes almost 100 years old with thatched roofs and concrete buildings well over the 30 year depreciation price, taxing is based upon the above method.