The biggest mistake contractors make is not tracking costs by job. When expenses go into generic categories like “materials” or “labor” without being assigned to specific projects, you have no idea which jobs are profitable. That remodel you thought went well might have actually lost money once you account for all the trips to the supplier, the extra labor hours, and the materials that got charged to the wrong project. Setting up proper job costing from the start prevents this problem entirely.

Mixing personal and business finances is the second most common problem. Using a personal card for job site purchases, running personal expenses through the business account, or paying yourself inconsistently all create a mess that’s expensive to untangle. Open a dedicated business bank account and credit card. Use them only for business. This single change makes bookkeeping dramatically easier.

Subcontractor payments get mishandled constantly. If you pay someone over $600 in a year, you need to issue a 1099-NEC. That means collecting W-9s before you pay them, not scrambling in January. Missing 1099s can trigger IRS penalties and the requirement doesn’t go away just because you forgot. Keep a system for tracking subcontractor payments throughout the year.

Most contractors reconcile their accounts monthly at best. Weekly is better. When you wait a month to match your records against your bank statement, you’ve forgotten what half the charges were for. Errors get buried. Duplicate charges slip through. Weekly reconciliation takes fifteen minutes and catches problems while the context is fresh.

Poor documentation costs contractors real money at tax time. Receipts fade, get lost, or sit in a pile until they’re useless. Take photos of receipts immediately with your phone and use an app that organizes them by vendor or job. When the IRS asks about that $2,400 charge at the lumber yard, “I think it was for the Henderson project” isn’t an acceptable answer.

Cash in the bank is not the same as profit. Progress payments from a big job can make you feel flush while the actual margins are thin or negative. Contractors who don’t understand their financials often spend money based on their bank balance, then struggle when the next job starts slow or a customer is late to pay. Your books should tell you what you actually earned, not just what came in.

Equipment purchases get mishandled by almost everyone without accounting help. That new truck or trailer might be a full deduction this year under Section 179, or it might need to be depreciated over several years. The choice affects your tax bill significantly. Most contractors either expense everything or depreciate everything without considering which approach actually benefits their situation.

If your books aren’t giving you useful information about job profitability and overall financial health, the underlying problem is usually one of these mistakes. Our bookkeeping services in Santa Fe include the kind of review that catches these issues before they become expensive problems.