The 3 Most Common Mistakes in Preparing Your Own Taxes

Tax Preparation: Learn from These Common Mistakes

None of us are perfect and we all make mistakes. Many mistakes are made simply due to insufficient information, or information not easily understood. Here I’ll explain the 3 most common mistakes we see on self-prepared tax returns. They are marital status, business deductions, and kids with jobs.

Marital status:

Your marital status for federal income tax purposes is determined for the entire year, on December 31. You may have been single for 10 months of the year and then married in November, or married for the first 8 months and divorced in August. You are either single, or married, on Dec 31. One can always choose to file ‘married filing separate’, but that is different than ‘single’ – there are different rules that apply for certain things, and state law can affect how married filing separate is treated.

There does exist an exception to be ‘treated’ as unmarried (allowing you to file head of household or single even though legally married), but this is for those who have been separated for at least the last 6 months of the tax year. This exception is not commonly met, and you are free to ignore that part of this information. If you just got married, you cannot be treated as unmarried.

Business deductions:

Finding a place to deduct an expense does not mean it is a qualified business deduction for you. Form Schedule C is where someone would report their business income and expenses before electing to be taxed as a corporation. The form is a standardized form with places for various deductions that apply. Often we see something like ‘utilities’ filled in for someone with a home based business, and they simply enter their entire utility bill into the field. What is required to deduct the appropriate portion of utilities, mortgage interest, or any other part business part personal use takes a bit of extra effort and research. While that can be accomplished by someone with determination, we recommend that you find a professional to prepare your tax return and help educate you about how it is all reported at least once.

It applies to all the fields present for business deductions. There may be a place for you to enter the expense, but it is not a simple plug and play form. One can read the instructions for the Form Schedule C which will identify most items one by one, but be ready for some boring reading!

Kids with jobs:

It is a sore subject for a parent when their young adult child whom is still a dependent filed their tax return very quickly for their refund, but accidently forgot the box that says they are a dependent – thus disallowing the parent(s) from claiming them or their college expenses.  If your child files a return before you file your tax return please double and triple check that they checked the box which indicates they are a dependent of another taxpayer (you).

The way it actually reads on the tax return (the 2017 Form 1040EZ) is ‘If someone can claim you as a dependent, check the applicable box’ and there is a box marked ‘You’. That box must be checked. If it is not checked, they are unable to be claimed as a dependent. It can be corrected, but it takes extra time and money to do so. Additionally, if the person is in college and you are paying for it – only claiming them as a dependent allows you to claim the college expenses on your tax return. If your child mistakenly did not check the box, not only can you not claim them, but you are losing potentially thousands of dollars of education tax credits as well. Due to this, we often advise parents to not let their children file a tax return until the parents return is filed and complete. It is much easier to correct one check box on the child’s return and resend it to the IRS, than have to go through and amend the child’s return which has to be filed on paper and takes the IRS 90+ days to process.

Charles Steinmetz
Senior Tax Professional

The Molen & Associates Difference

Mike Forsyth

“Super helpful and timely. This is our first year with them and we look forward to trusting them with our taxes and business books for years to come.”

Caitlin Daulong

“Molen & Associates is amazing! They run an incredibly streamlined process, which makes filing taxes a breeze. So impressed with their attention to detail, organization, and swift execution every year. Cannot recommend them enough!”

Sy Sahrai

“I’ve been with Mr. Molen’s company for few years and I felt treated like family respect and dignity. They are caring, professional and honest, which hard to find these days. Love working with them.”

Unlocking Real Estate Losses: Smart Tax Strategies for Investors

Real estate is more than just a path to passive income—it’s one of the most powerful tools in your tax-planning toolkit. When used strategically, real estate investments can generate significant “paper losses” that help lower your taxable income. But if the rules...

The Most Overlooked Small Business Tax Deductions—and What You Should Track Year-Round

What Do I Need to Keep Track of for My Small Business Taxes? Running a small business comes with a long to-do list—and tracking tax deductions is one item you can’t afford to ignore. Good recordkeeping and a solid understanding of deductible expenses can save you...

Year-End Tax Planning Strategies to Reduce Your Tax Bill Before December 31

Year-End Tax Planning Strategies to Reduce Your Tax Bill Before December 31 What you do before December 31 matters more than most people realize.Once the year ends, many of the most powerful tax-saving strategies are no longer available — no matter how good your...

Will You Receive a $2,000 Tariff Stimulus Check in 2025? What We Know So FarBy Molen & Associates | December 2025

You may have seen headlines or social media posts this fall about a possible $2,000 “tariff stimulus check”—a rebate proposal by President Donald Trump to send cash payments to Americans funded by tariffs on imported goods. Naturally, many of our clients have been...

Setting Up QuickBooks for Your Small Business: A Step-by-Step Guide

Why QuickBooks Setup Matters QuickBooks is one of the most powerful tools available for small business bookkeeping—but it’s only as good as the way it’s set up. A sloppy or incorrect setup can lead to misclassified income and expenses, messy financials, and costly tax...

Tax Planning for Business Owners: Moves to Make Before Year-End

Business Tax Planning You Should Know Business tax planning is the proactive process of analyzing your company’s financial position throughout the year to reduce your overall tax liability. It’s about more than just preparing your tax return—it’s about making...

Retirement and Taxes: Tips for Maximizing Social Security and Managing RMDs

Retirement should be a time of financial peace—not unexpected tax bills. But many retirees are surprised to find that their Social Security benefits are taxable, or that Required Minimum Distributions (RMDs) can push them into higher tax brackets. With a little...

Why Corporate Accounting Is the Foundation of Every Successful Business

In today’s competitive business landscape, strong financial management isn’t optional — it’s essential. Whether you’re a small startup or an established corporation, accurate and strategic corporate accounting helps you understand where your business stands, make...

Is Your Business Audit-Ready? Start with Proper Financial Statement Preparation

When it comes to business finances, one of the most important steps in maintaining transparency and compliance is Financial Statement Preparation. Whether you’re a small business owner or managing a growing corporation, your financial statements serve as the...

How Do I Pay Myself as a Business Owner? A Guide to Getting Paid Properly

Understanding Owner Compensation As a business owner, figuring out how to pay yourself isn’t as simple as just transferring money from your business account to your personal one. How and when you pay yourself depends on your business structure, your tax filing status,...

Request an Appointment Today

13 + 8 =

Call us at

Share This