The first year of working for yourself has a fairly consistent shape. The work goes better than expected or worse, the admin is more than anticipated either way, and somewhere around the following spring there’s a conversation with an accountant that doesn’t go how anyone hoped.

The surprises are predictable. Which means they’re avoidable, if someone mentions them early enough.

Nobody is withholding anything

This is the foundation of every other surprise.

As an employee, tax came out of each paycheck automatically. You saw a net figure and budgeted from it, and by the time you filed, most of what you owed had been paid. It was invisible and it was working.

Self-employed, every payment arrives gross. All of it looks like yours. None of the machinery that was quietly handling this still exists, and there’s no notification when it stops.

There’s an extra tax you may not know about

Employment income carries payroll taxes, and as an employee you paid a portion while your employer paid the rest. It appeared on your payslip as a deduction you probably never examined.

Self-employed, you’re generally responsible for both portions. It’s a distinct charge from income tax, calculated separately, and it applies to business profit.

This is the single largest source of first-year shock. People budget for income tax, having some sense of what rate they’re at, and are then presented with a further charge they’d never heard of. It’s not obscure — it’s just invisible from inside employment.

Payments are due through the year

Because nothing is withheld, the system generally expects instalments as you earn, rather than one payment at filing. Missing them can generate an underpayment charge even if you eventually pay in full — it’s charged on timing, not on the total.

The first year is where this bites hardest, because there’s no prior-year liability to reference and no established habit. Covered in more detail in our piece on estimated taxes.

What you can deduct is broader than you think, and narrower

Both directions, which is why it’s worth an actual conversation.

Broader: legitimate business expenses reduce the profit you’re taxed on. Equipment, software, professional fees, business insurance, business travel, part of your phone if used for business, potentially part of your home if you have a qualifying workspace. Many first-year self-employed people significantly under-claim because they don’t realize ordinary business costs count.

Narrower: the standard is that expenses be ordinary and necessary for the business. Personal costs don’t become deductible because the business paid them, and mixed-use items generally need apportioning. The confident advice circulating online about what you can write off is frequently wrong, and it’s you who defends it.

Start-up costs have their own treatment

Money spent getting the business going, before it actually started trading, is generally treated differently from ongoing expenses. There are specific provisions covering it.

The practical point: keep records of what you spent before you started, not just after. It’s a commonly missed category precisely because it predates the point at which people start keeping business records.

Separate the money on day one

The single highest-value habit, and it costs nothing.

A separate business bank account. All income in, all business expenses out, deliberate transfers to yourself. If you take one piece of advice from a first year, take this one.

It makes bookkeeping nearly mechanical, makes substantiating expenses straightforward, and prevents the year-end exercise of picking business transactions out of twelve months of personal spending. Owners who do this find the admin manageable. Owners who don’t find it miserable, every year.

Ideally a third account for tax money, funded by a percentage of every payment received.

Contemporaneous records or none

Records created at the time are substantially more useful than records reconstructed later — both for accuracy and for defending a position if it’s ever questioned.

The two that matter most: mileage, logged as you drive rather than estimated in April, and the business purpose of expenses, noted at the time. A receipt without context is weak support two years later when nobody remembers what the dinner was for.

Retirement options are actually better

A rare piece of good news. Self-employed people generally have access to retirement arrangements with considerably more capacity than a typical employee plan.

Several structures exist, with different contribution capacities, different administrative burdens, and different establishment deadlines. Some must be set up before year end even where funding can happen later — which means finding out about them in April can cost you a full year.

Worth asking about early rather than late.

What to do in month one

Separate account. Immediately.

Set aside a percentage of every payment. Ask an accountant for a realistic figure for your situation rather than guessing.

Start a simple record system. A spreadsheet is fine at first. Consistency matters more than sophistication.

Have one conversation with a preparer early. Not in April — now. An hour in your first months costs far less than the accumulated cost of a year of avoidable decisions.

Ask about structure and retirement. Both have timing constraints, and both are cheaper to handle before the year runs out.

None of this is difficult. It’s just genuinely not obvious from inside employment, where all of it was handled invisibly by someone else.

This article is general information, not tax advice. If you’re in your first year, get in touch — an early conversation is the cheapest one you’ll have.