Over 35 years of working with businesses at every stage of their development, I have seen the first-year mistakes play out repeatedly. They are not the dramatic failures of poor business ideas or bad management — they are the quietly expensive errors that come from simply not knowing what you don’t know.
The encouraging thing about most first-year financial mistakes is that they are recoverable. The discouraging thing is that they are almost entirely avoidable with the right advice at the right time. You will find more practical guidance across our business startup guides, but here are the seven I see most consistently.
Mistake 1: Not Separating Business and Personal Finances From Day One
This is the most common and the most consistently damaging. A new business owner opens a business, starts receiving income into their personal bank account, pays business expenses from the same account, and arrives at year end with a bank statement that is an indecipherable mix of business and personal transactions.
The consequences are practical: preparing the accounts costs significantly more when the accountant has to forensically reconstruct which transactions were business and which were personal. Claims are missed because receipts were not associated with the correct payments. Revenue queries are harder to answer because the records are not clean.
The fix is simple and costs nothing: open a dedicated business bank account before you start trading. Use it exclusively for business transactions. Pay yourself a defined draw from it rather than using the account as a personal wallet.
This single habit, established from week one, saves time, money, and stress every year.
Mistake 2: Not Setting Tax Money Aside As You Earn It
The Irish self-assessment system means sole traders pay their income tax in a lump sum in October, covering both the previous year’s balance and a preliminary payment for the current year. For someone accustomed to PAYE — where tax is deducted at source before pay arrives — this is a genuine shock.
In their first year, many new business owners spend everything they earn. October arrives. Their accountant tells them they owe €15,000 in income tax. The money is not there. They pay it from savings, or borrow, or — in the worst cases — don’t pay it and start accumulating a Revenue liability that compounds with interest.
The fix is to treat tax as a cost that accrues as you earn, not a bill that arrives once a year. Set aside a percentage of every payment received into a separate savings account. For most sole traders on typical margins, 25–30% is a conservative starting point. Your accountant will give you a more precise figure based on your expected income.
Mistake 3: Ignoring VAT Until Revenue Makes Contact
The VAT registration thresholds in Ireland are €40,000 for service businesses and €80,000 for goods businesses. These sound significant, but for a full-time self-employed person, the service threshold is not a high bar.
The mistake is treating VAT registration as something that happens eventually rather than something to monitor proactively. Revenue cross-references income tax returns against the VAT register. A business declaring €55,000 in turnover on its income tax return while not registered for VAT is easily identifiable.
Registration with back-dating, the payment of VAT that should have been collected, and the interest that accrues — all of this is avoided by monitoring your turnover against the threshold and registering proactively when you approach it.
Mistake 4: Confusing Turnover With Profit
I have had more than one conversation with a new business owner who is both proud and bewildered: “I’ve invoiced €80,000 this year — but I have no money.”
Turnover is not profit. The €80,000 is before materials, subcontractors, insurance, accountancy, motor expenses, phone, equipment depreciation, and the income tax on whatever is left. For many trades businesses, the net profit after all legitimate expenses is 40–60% of turnover. For service businesses with low direct costs but high overheads, the margin can be anywhere.
Understanding your gross margin and net profit — and watching them over time — is basic financial literacy for a business owner. It is not an accounting concept that only applies to large companies. It applies to every business from the first month of trading. Our guide on how to price your services as an Irish SME covers this in detail.
Ask your accountant to show you your gross margin and net margin in your first year accounts, and explain what the figures mean. If they are not doing this as a matter of course, ask for it specifically.
Mistake 5: Treating the Business Bank Account as a Personal Account
Related to Mistake 1 but distinct: even where a business owner has opened a separate account, many treat it as effectively a personal account — drawing money out whenever they need it, in whatever amounts, without any system.
For a sole trader, this is messy but legal. For a company director, it is a compliance problem. Drawing money from a limited company without following the correct procedures — salary through payroll, dividend declaration by shareholder resolution — creates director’s loan account issues, potential BIK exposures, and PAYE liabilities that are expensive to unwind.
Establish a clear mechanism for how money moves from the business to your personal finances: a regular salary, a defined dividend policy, or a clear draw schedule. Whatever the mechanism, it should be consistent and documented.
Mistake 6: Not Registering for Tax Before Starting to Trade
Revenue requires businesses to register before they commence trading. In practice, many new businesses start taking money from clients before they have registered with Revenue as self-employed or registered their company for corporation tax.
This is not a catastrophic error — Revenue accepts late registrations without significant penalty in most cases — but it starts the business relationship with Revenue on the wrong foot. It also means the first period of trading is occurring without the business being on Revenue’s radar, which creates reconciliation complications when registration eventually happens.
Register with Revenue before your first invoice. The process is straightforward through myAccount or ROS and takes a matter of days.
Mistake 7: Not Engaging an Accountant Until Year End
The most expensive version of this mistake is the business owner who spends an entire year making structural decisions — about their trading entity, about VAT, about how to pay themselves — and then discovers in February of the following year, when they sit down with an accountant for the first time, that several of those decisions were suboptimal and some are going to cost significant money to unwind.
The value of an accountant to a new business is front-loaded, not back-loaded. The structural decisions made in the first six months — entity choice, VAT approach, payroll setup, how to extract income, how to handle capital expenditure — shape the tax and compliance picture for years. Getting these right from the beginning is worth much more than the annual accounts preparation at year end.
An initial consultation with an accountant before you start trading, and a review conversation three to six months in, costs a fraction of the savings it generates. If you are not sure where to start, our guide on how to choose an accountant in Ireland explains the qualifications to look for and the questions to ask.
Paddy Malone FCA AITI
Paddy is the principal of Malone & Co. Chartered Accountants in Dundalk. A Fellow of Chartered Accountants Ireland and a Chartered Tax Consultant with the Irish Tax Institute, he has been advising businesses across County Louth and the North-East for over 35 years.