Tax collectors gather revenue by visiting cities, towns, estates or homes. Taxes, which are often paid in kind rather than coin, range from head-count tax (making the collectors essentially census takers as well), land and building tax (tax liability might be determined by anything from the number of rooms to the number of windows) and all sorts of other levies. Collectors might also sit at provincial or city borders to collect customs duties on goods passing through the region. Tax collectors are universally unpopular, and there is often little regulation to keep them from skimming funds or engaging in other sketchy practices.