If you are an employee or a sole proprietor who has business-related travel, entertainment, gift, or transportation expenses, you should consult irs.gov, particularly Publication 463 on Travel.

I learned that self-employed consultants, independent salespeople, small-business owners, and freelancers can regularly write off expenses on business trips. As long as business is the primary reason for travel, your airfare, lodging, meals, car rental, taxis, and even tips and laundry can all be deducted.

The IRS says “ordinary and necessary” expenses for business are 100 percent deductible. This includes:

- transportation
- lodging
- incidentals, such as Internet, phone, and laundry

Half of the costs of meals you incur because of work are deductible. You can eiter total up your receipts or use the government-approved allowance, which varies from city to city (from $31 to $46 a day).

If you’re driving your own car, the standard reimbursement is 37.5¢ per mile for 2004, upped to 40.5¢ for the 2005 tax year.

But don’t expect the IRS to take your word that the motive for that weekend in South Beach was for business. If you get audited, you’ll need receipts and meeting records to back you up.