What is the pay-as-you-go system of tax collection?

The pay-as-you-go system of tax collection obviously differs from the normal system of tax collection because instead of paying your taxes in lump sum on April 15th of every year, the taxpayer is obligated to pay their taxes in quarterly fashion, paying a fourth of the amount owed at four specific dates throughout the year. It is more common than most people think, as sometimes people are unable to pay in lump sum so they fill out a voucher for the IRS to allow them to pay whenever they get enough money throughout the year. For example, independent contractors who don't make a base salary, but make money based on their contracts are pretty much required to file quarterly. The IRS wants their taxpayers to pay their taxes whenever they receive their income, that way the IRS doesn't have to worry about delinquent taxes. Keep in mind, you must notify the IRS of your intentions of payment on taxes, before you file quarterly.