Why is it so important to separate business and personal finances?

Mixing the two is the most common mistake new self-employed people make, and it creates problems in three areas: taxes, liability, and sanity. At tax time, commingled accounts make it nearly impossible to cleanly identify deductible expenses, and the IRS scrutinizes businesses that look like hobbies. If you've formed an LLC or corporation, mixing funds — called piercing the corporate veil — can strip away the liability protection you set the entity up for. Practically, separate accounts give you a clear picture of whether the business is actually profitable instead of guessing. The fix is simple: open a dedicated business checking account and a business credit card, route all business income and expenses through them, and pay yourself by transferring to your personal account. Start the separation from day one rather than untangling a year of mixed transactions later.