Most small business owners did not start their business to do bookkeeping. They started it to build something. But the financial side of running a business does not wait — and the mistakes that pile up in the books quietly cost money, trigger IRS scrutiny, and make tax season far more painful than it needs to be. The good news is that the most common bookkeeping mistakes are also the most predictable ones. Here are the five we see most often — and what it takes to fix them. M