After 30+ years of cleaning up small-business books, we see the same handful of mistakes over and over. None of them come from carelessness - they come from busy owners doing their best without a system. Here are the seven that cost the most.
1. Mixing personal and business expenses
One bank account for everything means every statement line needs a judgement call at tax time. Deductions get missed, personal costs get claimed by accident (a CRA red flag), and your books stop reflecting reality. The fix is simple: separate accounts and cards, from day one.
2. Skipping bank reconciliation
Reconciliation - matching your books against your actual bank statements - is how errors, missed transactions, duplicate entries, and even fraud get caught. Books that are never reconciled drift further from the truth every month, and the year-end cleanup bill grows with them.
3. Losing receipts
CRA can deny a deduction you can't support, even when the expense was real. A shoebox is better than nothing, but a phone photo saved to a shared folder the day you get the receipt is better still. Six years of records is the standard CRA expectation.
4. Miscategorizing expenses
Meals at 50%, vehicle costs by business-use percentage, capital purchases depreciated rather than expensed - categorization rules decide what you can actually claim. Getting them wrong in either direction costs you: missed deductions or a reassessment.
5. Falling months behind
Bookkeeping postponed becomes bookkeeping forgotten. Reconstructing a year of transactions from statements takes far longer (and costs far more) than maintaining them monthly - and in the meantime you're running the business blind.
6. Ignoring GST obligations
Once your revenue passes $30,000 over four consecutive quarters, registration isn't optional. We regularly meet owners who crossed the threshold without noticing and now owe GST they never collected. Watch the number - or have someone watch it for you.
7. Never looking at the reports
Books aren't just for CRA. A monthly profit-and-loss review is where you notice a margin slipping, a cost creeping, or a customer who isn't paying. If your bookkeeping produces no information you actually use, something is wrong with the setup.
The common thread
Every one of these is cheaper to prevent than to fix. If your books need a rescue - or you'd just rather never think about them again - book a free consultation. Catch-up bookkeeping is one of our specialties, and we don't judge.