Ten minutes a month or a lost weekend in April. Setting up records that hold

Set this up once and the work is ten minutes at the end of each month. Skip it and the same work costs a weekend in April, done badly, from incomplete information, with real deductions missing because nothing supports them.

The sequence below is the whole system.

Step one: separate the accounts

One bank account and one card used only for business. This is the single highest-value step and it takes an afternoon.

What it buys is not tidiness. It is that the account statement becomes an independent record of the business, which means the categorization work has a source document behind it and a mixed transaction is the exception rather than the default.

If money moves between personal and business, move it as a transfer with a label, not as an ad hoc payment.

Step two: choose categories that match the form

Do not invent a chart of accounts. Copy the expense lines from the schedule you will actually file, add the two or three specific to your work, and stop there.

Categories that map directly to the return mean the year-end work is transcription rather than interpretation. The IRS publishes the forms and their instructions, and the instructions for the expense lines answer most categorization questions in a paragraph.

Step three: the monthly ten minutes

Pick a date. The first Saturday, the last day of the month, whatever recurs.

1. Download or open the month's statements for both accounts.
2. Assign every line a category. Anything you cannot categorize in ten seconds gets flagged rather than guessed.
3. Attach receipts for anything unusual or over your own threshold. Photograph and file by date.
4. Note the month's mileage total from wherever you record trips.
5. Reconcile: the ending balance on the statement matches your record. If it does not, the discrepancy is this month's problem rather than next April's mystery.

Ten minutes is realistic once the accounts are separated. It is not realistic if you are also untangling personal spending, which is the argument for step one.

Step four: the records that are worth more than they look

• Mileage, logged when it happens. Date, purpose, and either odometer readings or the distance. Reconstructed mileage is the most commonly disallowed deduction there is, and the reconstruction takes longer than the logging would have.
• Asset purchases with dates and amounts. Anything with a useful life beyond a year is handled differently from a supply, and the decision needs the purchase date.
• Home office square footage, measured once and written down, along with the total square footage of the home.
• Contractor payments, with the payee's tax identification information collected at the time of the first payment rather than in January. Collecting it later is the annual scramble every small business recognizes.
• Loan statements, so that interest and principal are separated rather than treated as one expense.

The expenses people leave on the table

These are ordinary, they are supportable, and they get missed because nothing prompts for them.

• Health insurance premiums paid by a self-employed person.
• The deductible portion of self-employment tax.
• Retirement contributions still available after the year has closed.
• Bank and payment processing fees, which are small monthly and meaningful annually.
• Professional subscriptions, licenses, and continuing education that maintains an existing skill.
• A portion of a phone or internet bill actually used for the business.

None of these are aggressive positions. They are lines on the form that stay blank because nobody recorded the underlying spending.

The expenses people invent

Two failures show up repeatedly. Personal costs recategorized because they occurred during a working day, and mixed-use items claimed at full business use. A vehicle used for errands and for work is a proportion, and the proportion needs a basis. Clothing that could be worn anywhere is not a business expense however specifically it was bought.

Claiming these is not a gray area, and they are the entries most likely to draw a question about everything around them.

What to keep, and for how long

Keep the return, the supporting records, and anything establishing the basis of an asset. Records supporting income and deductions are generally kept for several years after filing, and records establishing the cost of property are kept for as long as you own it plus that period afterward.

Digital copies filed by year and month are sufficient for almost everything. Name them so they sort themselves and keep a second copy somewhere other than the computer they were made on.

Set up this way, the April task is opening twelve folders and adding up columns that were already correct. The preparer's fee, if you use one, drops to the low end of their range, because you are paying for judgment rather than for sorting.