Did you know that if your Federal tax owed on your tax return is more than $1,000 you might have to pay a penalty? The way to avoid that is by paying in at least what your total Federal tax liability was for the prior year (same rule is for the state return). This is accomplished by paying in that amount over four installments (estimated tax payments). But many find themselves owing a large amount at those times. Another solution is to pay an amount monthly that will be enough to cover your projected total Federal tax so that you do not have such a large liability when the return is due. This procedure can also be applied to the filing of your Oregon income tax.
Keep in mind that these rules are only effective up until the due date of the return, usually April 15th. If you owe after that date, you may have penalties and interest assessed by both The IRS and the applicable states.