Most self-prepared-return problems are not caused by a person being careless. They often arise because tax law uses concepts that are easy to misunderstand or because the software cannot know a fact was omitted. Do any of these resonate with you?
“I entered the same income in two different places.”
This can happen when income is first included in business or investment activity and then entered again after an interview question appears to ask about the same event in a different way.
“The brokerage statement showed basis as zero, so I used zero.”
Brokerage reporting can be incomplete for older holdings, inherited assets, transferred accounts, stock compensation, or transactions where basis adjustments are not obvious.
“I deducted the whole business purchase because I paid for it this year.”
Some expenditures must be capitalized or depreciated. Others may qualify for immediate expensing or bonus depreciation. Classification and elections matter.
“I contributed to an IRA, so I deducted it.”
Deductibility can depend on income and workplace retirement-plan coverage. Nondeductible contributions also require basis tracking to avoid paying tax twice later.
“I withdrew from an inherited IRA, but I did not realize there could also be annual beneficiary RMD rules.”
The 10-year regime can involve annual required distributions for some beneficiaries and full depletion by the end of the applicable period. Planning matters as much as compliance.
“I moved, so I just filed in the state where I live now.”
Part-year residency, prior-state income, credits, withholding, and business or rental activity may require more than one state return.
“My K-1 showed a loss, so I deducted it.”
Basis, at-risk rules, and passive-activity limitations can restrict current deductions even when a K-1 reports a loss.
“The software asked whether my child was my dependent, and the answer seemed obvious.”
Dependency, filing status, child tax credit, education benefits, and support rules can use different statutory tests. Everyday family arrangements do not always map neatly to tax definitions.
“I forgot about a carryforward from last year.”
Capital losses, passive losses, credits, basis schedules, charitable contributions, and other tax attributes can carry into future years. Switching software or starting a return from scratch can break that chain.
“The refund looked good, so I assumed the return was right.”
A result that feels favorable is not a substitute for reconciliation. Refund size can be driven by withholding and payments rather than whether the tax itself was calculated correctly.