I think it would be great feature if you had to pay pay taxes every week. The Monday could be the pay day (or any other). When you get up the money the money will be automatically deducted from your wallet (similar to Doctor) or like other screen when you receive your earnings from shipments This would be another variable to consider before spend your money (I need have X amount to pay the taxes of this week). I don't know which could be the penalty fee for don't pay the week taxes, maybe the tax will accumulate if don't pay and you will pay extra tax next week. I think would be fun when you start a new game because it will be more difficult to make money at the beginning. And, maybe, the fee of the taxes can increase every year, or according to your buildings (that you have built in farm).