The habits that keep your business compliant, profitable, and penalty-free, and the common mistakes we see far too often.
After working with hundreds of businesses, we’ve noticed the same patterns. Successful business owners do certain things consistently. Costly mistakes are almost always avoidable. Here’s the definitive list.
Record Keeping
- DO:
- Keep a dedicated business bank account — even as a sole trader
- Photograph and store every receipt digitally (Xero or Dext work brilliantly)
- Reconcile your accounts monthly, not at year-end
- Retain records for at least 6 years — HMRC can go back that far
DON’T:
- Mix personal and business spending on the same card
- Rely on a shoebox of paper receipts at year-end
- Delete bank statements or emails — HMRC considers these records
- Assume your accountant will ‘sort it out’ without your input
VAT & Expenses
DO:
- Claim all legitimate business expenses — including home office, mileage, and phone
- Register for VAT voluntarily if you’re close to the threshold — it can improve cash flow
- Review your VAT scheme annually (Flat Rate vs Standard can make a big difference)
- Use HMRC’s approved mileage rates (45p for first 10,000 miles in 2025/26)
DON’T:
- Claim personal meals, clothing, or holidays as business expenses
- Miss your VAT registration deadline — penalties start immediately
- Submit a VAT return with figures you haven’t verified — errors attract enquiries
- Forget to reclaim VAT on large capital purchases
Payroll & Employees
- DO:
- Enrol eligible employees into a workplace pension — it’s a legal requirement
- Use salary sacrifice to reduce your Employer NI bill where possible
- Claim Employment Allowance if eligible (up to £10,500 in 2025/26)
- Issue P60s by 31 May and P11Ds by 6 July each year
DON’T:- Pay staff informally ‘off the books’ — the penalties are severe
- Ignore the new Employer NI rate — budget for it now, not at the end of the year
- Treat employees as contractors to avoid NI — HMRC is actively targeting this
- Miss RTI (Real Time Information) PAYE submissions — fines apply per late filing
THE GOLDEN RULE: The single most expensive mistake we see is leaving everything until the last minute. Rushed accounts lead to missed deductions, errors that invite HMRC scrutiny, and stress you simply don't need. Good accounting is 80% habit and 20% expertise. We can help you build the habits — and handle the expertise.
Self Assessment
- DO:
- File early — ideally before October to know your liability and plan ahead
- Set aside roughly 20–30% of profit monthly for your tax bill
- Declare all income sources, including rental, dividends, and freelance work
- Check whether payments on account can be reduced if your income has dropped
DON’T:- Miss the 31 January deadline — even a day late triggers a £100 fine
- Assume HMRC will tell you that you owe money — the responsibility is yours
- Guess figures or round numbers heavily — this flags your return for review
- Forget to declare income from online platforms (HMRC receives reports directly)