The only time you would likely have to deal with the IRS is when they want you to pay up your tax money. Dealing with the IRS can be made easier and more pleasant when you follow certain guidelines.
Firstly, you should never ignore the IRS. If they send you a letter it’s for a reason, usually to inform you of an assessment of your taxes and demand payment. So always reply to their letters or notices within their deadline (usually 30 days). The longer you ignore your business's tax problems, the larger your tax debt will grow. Currently, most tax debts compound at a rate up to 14%. If you fail to reply to the IRS, whatever assessment they calculated would be deemed final. If the IRS writes to you requesting for some document like a previous year’s tax return or inform you of some action they are about to take such as garnering your wages or levying your property, you should cooperate and provide the information that is sought. However, full disclosure may not be a good idea. You should not lie to the IRS, yet you aren't legally required to disclose anything about your finances or assets to the IRS collector unless you are formally served with a summons.
Secondly, if the IRS is assessing a revised tax liability for you, you should investigate their assessment. Then the appropriate action can be taken accordingly. For example if the IRS filed a substitute return on your behalf because you missed a tax return in any year then you should file a tax return for that delinquent year. If you are an innocent spouse being charged for your spouse’s tax liability, then you can resolve the issue by filing an innocent spouse relief. Perhaps the IRS has assessed penalties against you for which you should seek abatement or the IRS is seeking payment of taxes that were due longer than the statute of limitation (usually 10 years). Whatever the case is, you can only deal with the IRS appropriately after you have investigated their assessment.
Thirdly, assuming you have agreed to the amount of your tax liability, you should consider asking the IRS for a payment plan. In most cases, the IRS allows payment by monthly installments. But, you should remember that interest and penalties are always accumulating. You can also try to negotiate a discount on the total amount you owe.
Besides an installment agreement, there are other methods to clear tax debt such as an offer in compromise, a “not collectible” classification or file a bankruptcy petition. However, bankruptcy can eliminate tax debt only if it can be proven that the debt will severely affect your means of survival. So the other options are more realistic.