Lean Season Checklist: Common Tax Filing Mistakes You Can Avoid Next Year—Start Today

Insights from a Filipino Accountant Who’s Seen It All

As an accountant who has helped dozens of business owners navigate the tax season here in the Philippines, I can tell you—many of the problems that show up during tax filing are completely avoidable. The key is preparation, and there’s no better time to start than right now, during the tax lean season.

In this blog, I’ll share some of the most common tax filing mistakes I’ve encountered from actual clients—along with how you can avoid them by putting proper systems and controls in place today. Whether you’re a sole proprietor or running a growing SME, these tips will save you time, money, and headaches when tax season rolls around again.

🔍 Mistake #1: Incomplete or Missing Receipts

What usually happens:
Clients scramble during filing season because important receipts are missing or crumpled at the bottom of drawers. This leads to underclaimed expenses and higher tax dues.

How to avoid it:
During this lean season, set up a receipt documentation system. I helped one client implement a monthly folder system—physical and digital. They saved over ₱35,000 in additional allowable deductions the following year just by keeping better records.

🔍 Mistake #2: Mixing Personal and Business Expenses

What usually happens:
Owners swipe the same card for groceries and inventory. When tax season comes, it’s hard to identify legitimate deductions.

How to avoid it:
Open a separate bank account and e-wallet for business transactions. We also encourage using bookkeeping software or templates that track business-only expenses. It’s a simple change, but one that can save you from disallowed deductions during audit.

🔍 Mistake #3: Late or Incorrect Tax Form Filing

What usually happens:
Many business owners forget deadlines or file the wrong BIR forms (e.g., 2551Q instead of 2551M, or vice versa).

How to avoid it:
Set up a compliance calendar now. We do this for every client—listing all deadlines (monthly, quarterly, and annual), with email or phone reminders. This also helps the team plan ahead and avoid the last-minute filing rush.

🔍 Mistake #4: Unreconciled Books

What usually happens:
Income reported to the BIR doesn’t match the books, or expenses are missing. This creates red flags during BIR audit or LOA (Letter of Authority) investigations.

How to avoid it:
Do monthly reconciliations of your cash, bank accounts, and ledgers. I once found a ₱120,000 discrepancy in a client’s records because deposits were recorded twice. Catching it early prevented tax overpayment.

🔍 Mistake #5: Using an Outdated Chart of Accounts

What usually happens:
Your chart of accounts doesn’t reflect your business anymore—making reports confusing and tax summaries inaccurate.

How to avoid it:
We customize and streamline the Chart of Accounts for each business we handle, making reports cleaner and categories more aligned with both BIR and management needs.

🔍 Mistake #6: Relying Only on Year-End Cleanup

What usually happens:
Books are untouched all year, then rushed in February or March. This leads to errors, missed expenses, and burn out.

How to avoid it:
Switch to monthly or quarterly bookkeeping. Even a basic routine of encoding sales and expenses every 15th and 30th will make year-end smoother. You don’t need to wait for chaos to happen.

✅ Lean Season Action Plan: What to Do Today

• ✅ Organize receipts and invoices from January to May

• ✅ Review your BIR form submissions from Q1

• ✅ Reconcile your bank and cash accounts

• ✅ Create a tax deadline calendar

• ✅ Clean and restructure your Chart of Accounts

• ✅ Book a review session with your accountant
  
  

👩‍💼 Final Thoughts: Don’t Wait for the Crunch

Tax season is not meant to be painful—it only becomes that way when we ignore the small tasks throughout the year. As an accountant, I’ve seen businesses thrive simply because they took the lean season seriously.

This is your chance to build the foundation for a stress-free tax season next year. Don’t just “get by”—get ahead.

Need help with any item on the checklist? Let’s do a lean season review and make sure your systems are clean, compliant, and audit-ready before the next wave hits. You’ll thank yourself next April.