Expenses including fees and tips for porters, baggage handlers and other personal service employees. These expenses are part of the "meals and incidental expenses reimbursement" rates provided by the IRS. Unreimbursed incidental expenses are deductible according to a schedule prescribed by the IRS.
Incidental expenses that are incurred as a result of casualty or theft, such as emergency room treatment for injury suffered as a result of mugging, are not deductible as a casualty loss.
Also note that incidental expense rates differ by region.
