1.) Does my wife need to pay quarterly in her first year of business? (Lots of contradictory info out there on this one)  Maybe ... see other answers. 

2.) "Do you expect to owe more than $1000 in taxes?" is a question on the IRS site.  Does 'owe' refer to total tax liability for us, or what we think we would have to pay into the IRS after completing our return? (We expect her to do about the same income as she has been doing as a W2 employee for the last decade once she is out on her own performing the same job independently.  In the past, we have typically been refunded all of the federal taxes that she has paid in over the year.)  Net balance due of $1000  AFTER all the credits and withholding payments have been taken into consideration.

3.) IF our income remains the same as it has been for several years, would adjusting my withholding (if necessary) allow us to avoid paying quarterly?  My withholding (typically) is enough to cover our final tax liability.  Prepayments of taxes can be done thru withholding or estimates or any combination of them both.  On a joint return the payments from all sources are combined. 

PAYING ESTIMATES
For SE self employment tax - if you have a net profit (after expenses) of $400 or more you will pay 15.3% for 2017  SE Tax on 92.35% of your net profit in addition to your regular income tax on it. So if you have other income like W2 income your extra business income might put you into a higher tax bracket.

You must make quarterly estimated tax payments for the current tax year (or next year) if both of the following apply:
- 1. You expect to owe at least $1,000 in tax for the current tax year, after subtracting your withholding and credits. 
 
- 2. You expect your withholding and credits to be less than the smaller of: 
    90% of the tax to be shown on your current year’s tax return, or 
  100% of the tax shown on your prior year’s tax return. (Your prior year tax return must cover all 12 months.)

To prepare estimates for next year, You can just type W4 in the search box at the top of your return , click on Find. Then Click on Jump To and it will take you to the estimated tax payments section. Say no to changing your W-4 and the next screen will start the estimated taxes section.

OR Go to….
Federal Taxes or Personal (H&B version)
Other Tax Situations
Other Tax Forms
Form W-4 and Estimated Taxes - Click the Start or Update button

How does my side job affect my taxes?

You’re considered self-employed—even if it’s just something you do on the side, like drive for Uber, babysit, or blog.

Your taxes are handled differently than when you’re an employee of a company.

As a self-employed individual you:

• will pay self-employment tax (because income tax and Social Security aren’t deducted from your pay)
• will get a 1099-NEC or 1099-K (unless you only accept cash or personal checks)
• file a Schedule C, Form 1040 (this is how you report business expense or loss of income)
• can deduct money you spent on work-related expenses (like mileage, home office expenses, and cell phone use)
• can estimate the taxes that are due and make quarterly estimated tax payments during the year

Get started by entering your income from self-employment. We’ll handle the rest, from creating the forms you need to reviewing work-related expenses that can help reduce your taxes.