Self-assessment season: the October routine that makes January painless

Every January, accountants across the UK watch the same ritual play out: a wave of sole traders and landlords arriving in the final fortnight before the self-assessment deadline, armed with carrier bags of receipts and a rough guess at their income. It is stressful for them, and it is entirely avoidable. The accountants who handle January well built the habits in October.

I have prepared hundreds of self-assessment returns over the years, and the difference between a smooth return and a nightmare is almost never about tax planning. It is about record-keeping done steadily through the year. October is the perfect moment to set that up, because there is still time to catch up before the 31 January deadline without panic.

Start with a single October review

Block out one evening this month and pull together everything you have so far for the tax year: bank statements, invoices issued, purchase receipts, records of rental income, pension contributions and charitable donations. You are not doing the tax return now, only checking what exists and what is missing.

If you find gaps, October gives you room to fix them. A missing receipt from May can often be recovered from a supplier while the transaction is still fresh. In January, with thousands of others doing the same thing, that email takes a week to get answered.

Keep a running expenses list from now on

From today, keep one simple list, a spreadsheet is fine, of every business expense as it happens. Date, supplier, amount, what it was for. Do this weekly and it takes five minutes. Leave it until January and the same job takes a Saturday.

The discipline matters most for mixed expenses. If you work from home, note the proportion of household costs you intend to claim, using HMRC's simplified expenses or your actual figures consistently. If you use a car, record business mileage as you travel. These are the claims people most often forget, and they are legitimate money.

Do not forget the payments on account

One of the most common January shocks is the payment on account system. If your previous tax bill was over £1,000, HMRC collects your next bill in two instalments, in January and July, each based on half of your last bill. New self-assessment filers are often blindsided when their first January bill arrives at roughly one and a half times the tax they expected.

Checking your payment-on-account position in October gives you time to set aside the cash. It will not reduce the bill, but it removes the surprise, and surprises are what cause late payments and penalties.

Gather the documents that slow people down

Certain documents take time to track down, and they are the same ones every year. If you have a P60 or P45 from employment alongside self-employment income, locate it now. Pension providers issue annual statements that arrive late in the year; check whether yours has come through. If you made any Capital Gains Tax reportable disposals, make sure you have the acquisition and sale figures, plus any costs.

Landlords should gather rent statements, letting agent statements, and receipts for repairs done during the year. This is also the moment to check whether your expense records distinguish repairs from improvements, because only repairs are deductible against rental income.

When October preparation still is not enough

Some years, no amount of October routine will fix a chaotic position. Maybe you took on new income streams, moved from sole trader toward a limited company, or your rental portfolio grew faster than your record-keeping. In that case, getting professional support with corporation tax and self-assessment can be the difference between an accurate return and an expensive guess.

At Finex Outsourcing, self-assessment preparation is handled by accountants who work through returns methodically, chasing down missing figures and checking claims properly rather than rushing them in the final week of January. That is exactly the kind of calm, systematic approach that October preparation is meant to create.

A January you will barely notice

Here is the honest truth: nobody enjoys doing a tax return. But there is an enormous difference between a January return built on eight months of tidy records and one built on a shoebox. The first takes a couple of hours and a calm mind. The second takes a weekend.

Start the routine this October. Future you, the one sitting comfortably in mid-January with a submitted return and no deadline anxiety, will be glad you did.