None of these mistakes is dramatic. Each one is a small shortcut that works fine for a month and compounds for a year. By the time it surfaces, the fix is reconstruction rather than correction.
Every entry pairs the mistake with the habit that prevents it.
How we ordered them
- Cost when found late. How much work, and how much risk on the return, the mistake creates if nobody catches it until year end.
- How common it is. Mistakes that show up in most owner-led books rank above rarer ones.
The ten mistakes
1.Mixing business and personal money
Best for: Fix first — every other fix depends on it
Business spending on personal cards and personal bills paid from the business account mean every transaction has to be sorted by memory. Fix: a dedicated business account and card, and a routine owner transfer.
Read more →2.Not reconciling to the bank
Best for: The mistake that hides all the others
Bank feeds import transactions; they do not prove the books are complete. Without a monthly reconciliation, duplicates, missing deposits and transfers recorded as income go unnoticed. Fix: reconcile every account, every month, to the statement balance.
3.Letting the books fall months behind
Best for: Owners who plan to catch up in spring
Twelve months of transactions entered in March is a different job from one month entered each month — the receipts are gone and the context is forgotten. Fix: a fixed monthly close date, or a bookkeeper who keeps one.
Read more →4.Recording owner draws as expenses
Best for: Sole proprietors and LLC owners
Money you take out for yourself is not a business expense. Booking it as one understates profit and creates a return that does not match the bank. Fix: an equity account for draws, used every time.
5.Recording loan payments entirely as expense
Best for: Businesses with equipment or vehicle loans
Only the interest portion of a loan payment is an expense; principal reduces the liability. Fix: split each payment using the lender's statement, and check the loan balance on the balance sheet against it.
6.Treating transfers between accounts as income
Best for: Businesses with savings, credit card or payment-processor accounts
Moving money from savings to checking, or a processor payout arriving, is not new revenue. Recorded as income, it overstates what you owe tax on. Fix: record transfers as transfers and make sure both sides match.
7.No receipts for expenses
Best for: Anyone who spends by card
A bank line shows you paid; it does not always show what the expense was for. Fix: capture receipts when you spend and attach them to the transaction.
Read more →8.Misclassifying workers
Best for: Businesses paying helpers or subcontractors
Whether someone is an employee or an independent contractor depends on the working relationship, not on what you call them — and Massachusetts applies its own test, which is stricter than the federal one. Fix: decide deliberately, collect a Form W-9 from every contractor before paying, and ask if you are unsure.
Read more →9.Missing contractor information returns
Best for: Businesses paying contractors
Payments to contractors can require a Form 1099-NEC. For payments made after December 31, 2025, the reporting threshold rose from $600 to $2,000. Fix: track contractor payments by vendor through the year so the January count is a report, not a hunt.
10.Never looking at the reports
Best for: Owners whose books are only for the tax return
Books kept only for the return are paid for twice and used once. Fix: a short monthly look at the profit and loss and balance sheet.
Read more →
General information, not advice for your specific situation. Tax rules, prices and product features change, and firms change what they offer — check with the provider before relying on anything here, and talk to us or another qualified professional before acting on it.