If the government owes you money back you have up to 3 years to claim it and they may owe you interest, hopefully they have to pay you interest but if you owe them money and didn't file on time you will be charged a monthly penalty up to 5% I believe. So it's always best to do your taxes on time. It doesn't matter how old the debt is they want their money. It's funny how they act like it's water under the bridge when they owe you money though you better claim it in 3 years or you can forget about it.
